(It's been a such a long time since my last post so forgive the length of this.....)
For me, Marie Antoinette had many virtues and many faults. I do like her very much (as well as her sisters) and have been reading a lot of sources on her and her Austrian family... although I would not go so far as calling her a martyr.
IMHO, she did show a lot of kindness when she personally encountered hardship by her subjects but in general, she had no clue on what was happening in France (she never saw anything of France except during her bridal journey, did she?) and how the people were suffering..... she did cut down on her expenditures but only because of the looming national bankruptcy. True, she was said to be charitable but let's not forget, France then had a population of around 20 million people --- how many had she helped -- hundreds, a few thousands perhaps, out of those millions? Her dresses, her jewelry, her headdresses, her gambling debts, and her pleasures were too conspicuous for the rest of the people....what was the ratio of the money she gave to charity compared to her other expenses?
It is true that she has calmed down after having children but did not also let go of her frivolous Private Society and her expensive (and sometimes dangerous) pleasures, not to mention spending more and more time in Petit Trianon; one play was intially banned by Louis XVI for being dangerous to monarchy/nobility yet she insisted on having it performed in her private theatricals. The writer of said play had previously written a lewd pamphlet on her husband's impotence and even had the gall to send a copy to the (enraged) Maria Theresa but she fought to have his play performed.......such an unwise decision, and all in the pursuit of pleasure and what was 'in'.
She disdained those lewd pamphlets about her yet did nothing effective to counter them..... she probably thought they weren't to be taken seriously and look what happened. She knew she offended many of the nobles at court yet did nothing to conciliate with them. I'm of the opinion that she was not stupid but she seemed to have no clue that the French monarchy was tottering or if she did, she did nothing effective to prop it up. She was initially very popular and had other chances when Marie-Therese and Louis-Joseph were born but did nothing to assure her popularity, either with the masses or the nobles (preferably both). It's true that she had no real political role as Queen but she had quite considerable patronage --- and all she seemed to do with it was grant her special friends favors and costly posts.
Of course, it wasn't her fault that the French monarchy and economy were on the brink of ruin (Louis XV reportedly said, 'After me, the deluge.') but her lifestyle and decisions did not help things either. She was warned enough by her mother and brother (Joseph II). All in all, I think she had very little political acumen and that was her downfall...... even in familial matters, she did not bother to look into the future. One telling situation was her relationship with brother Leopold. She didn't have much to do with him, who left Vienna when she was 10, it was said that they never got along. Yet he was to be ruler of Austria.... but MA did not bother to cultivate any real relationship with him in all those years. As it were, she had to admit when Joseph died that she had absolutely no influence on her other brother.... so the kind of help that she wanted was not assured.
Having said all this, I do like her a lot and have a lot of sympathy for her.... as Dauphine, as Queen, and as the 'Widow Capet'. She did not deserve death. I think she had a good heart and wanted to do good (only what she did wasn't enough) and was courageous, especially in her last months. She was also, after all, a mere pawn of her mother. To send an almost illiterate, untrained, lazy, frivolous, and flighty (no matter how pretty, charming and affable) 14-year old to represent Austrian interests in a court that was anti-Austrian and one that resembled a snake pit (IMHO) seems like a recipe for disaster to me. Maria Theresa may have assuaged her conscience by sending her daughter numerous letters and advice as well as her best and most trusted diplomat, the ever-vigilant Count Mercy, to guide young Antoine, but she also had no personal idea of what her daughter was facing. Her scolding, nagging letters also did not help for they only assured that MA would rebel (albeit in a subtle matter, by lying and evasion). I don't think Maria Theresa ever considered how hard things were for her daughters --- she just wanted total obedience at all times. I admit that I find a lot of her advice good and quite practical -- IMO, the problem was her dictatorial tone as well as the incomplete/false reports that she took as gospel truth (she distrusted her children to a great extent, even when they were mere children).
MA's sisters, Maria Amalia and Maria Carolina, were also married to unsatisfactory men -- although they did not have the humiliation of an unconsummated marriage like hers for 7 years. Both sisters coped with their situation in their own way but they, at least, managed to hold on to their thrones until the Napoleonic Wars. Of course, Naples/Sicily and Parma were not as 'problematic' as France but I also think that Marie Antoinette's sisters had a lot more energy than she did in terms of public service and cultivating their people's affection....Perhaps that was why, despite being noted as proud, interfering/dominating consorts as well spending money like water and having (rumored) lovers (same accusations as with MA),they were not hated by their people (I should note that Maria Carolina also experienced a decline in popularity in the 1790s onwards so perhaps she was hated at a lesser degree). All 3 archduchesses were said to be capricous, frivolous, and willful...all had their enemies and were certainly viewed as pro-Austrian but MA's sisters definitely survived their situation (albeit being exiled)....Of course, MC had a seat in the state council and was the de facto ruler of her husband's kingdom while Marie Antoinette had no such official role in the government. Not sure about Amalia, I think she had no official role too, but just interfered as she pleased. Nevertheless, she was popular and seemed to have had an extraordinary reputation (in a good way) in Parma (despite the many 'scandals' earlier) to the day when she left in exile.
Just my two cents......