He did, he also inspired a generation of "hustlers" to rap for a come up with that "I'm a hustla not a rapper" shyt. Though I understand what he was REALLY getting at.
Rap is a skill, not who you are. Jay was a natural born hustla/salesman that picked up and honed the skill of rapping. He was 100% right to say it how he said it but nikkas took it like simpletons as an excuse to whore out the game. They jumped straight to capitalizing off of rap instead of actually trying to further their skill in it.
And then the whole "I don't write" shyt made it even worse. Constructing rhymes in your head is a viable way to learn/apply rap skills. If you have shytty hand writing (like me) or you think faster than you can write that might be the easiest way to do it, it ain't rocket science. The brain is a remarkable tool. But then that became an excuse to 'freestyle' and punch in rhymes only to brag about how much effort you didn't put into creating that rap.