In chapter 8, Mr Darcy says : "I cannot boast of knowing half a dozen, in the whole range of my acquaintance, that are really accomplished."
I understand there, that he has a large number of young women in his acquaintance; which is not surprising, as we can guess that to such an "eligible" man, every person in his acquaintance had presented several young ladies (we don't know his age yet, do we?) - all of them "very accomplished" of course, as it was, with beauty, fortune and birth, the measure of a girls "marriability".
There is a similarity between Regency and our time, in this. And how many stupid women don't we see getting the best diplomas, then climbing in a career? "So very accomplished"... but without real sense and even less sensibility. Mary Bennets instead of Elizabeth Bennets...
So, I think I understand what you mean by "inexperience". At Netherfield he is still believing in the accomplishments standards but has never met with a woman worthy of his love (humility is not his first merit, and Mrs Reynolds thinks the same after all). What could be his expectations then? If he had never known a woman with both brain and heart (and humour)... Would it have been so ununderstandable that he didn't imagine a perfect woman should exist? With or without sexist prejudice... After all Charlotte had a similar opinion upon men and marriage, hadn't she? And Mr Darcy had less inducement to seek a wife.