Ignorance != stupidity.
Unfortunately, ignorance is quickly developing into something much worse.
I encounter people every day who actively refuse to learn anything that takes more than 3 seconds to comprehend.
I won't judge you for the things you never had the chance to learn, but that changes the minute you choose not to think about something.
As for the original discussion, I sincerely hope that society will never reach the point where "it doesn't matter".
That said, hope and belief are two different things.
Grammar is being largely ignored by the masses.
I don't see this changing anytime soon. Like so many things, there is a self-reinforcing feedback loop.
People don't use grammar, so more and more people can "function" without having to learn it.
Conversational Logic and formal debate are also completely ignored by the masses.
That doesn't make them important and useful tools.