Well you are certainly entitled to your opinion. IMO she could go on a holiday once a month, as long as she isn't cheating anyone, kicking any dogs, doing drugs, acting like a fool while on holiday....who cares? In addition, the only people who should be hounding her to get a job is her parents, cause they are the one supporting her.
If she does marry William and becomes a part of the "Firm" her lack of answering the phones, getting coffee, typing memos, making sales calls or whatever are not indications on whether or not she could attend official functions...where honestly...the only thing she needs to do is make a speech (not even written by her), stand quietly in the background, do her walk abouts, open a hospital, etc or produce the next heir. Basically support her husband. Not to be funny...but isn't that what Camilla does? Sophie?