Yeah ... If you have NO other back end capabilities than Access, then it's better-than-not to have SP added to the toolbox.
Although I work for a big global company, my specific dept has been fighting to get SQL Server access and we haven't (yet). I miss it, and am not used to not having it. In its absence, people have gotten used to using SP for absolutely "everything", short of major enterprise apps. I've been on a campaign to educate and persuade that in some cases we might be over-using SP if an Access app could be much more infinitely and quickly customized. Add to all this that we aren't given SP Designer! We're still on SP 2010 and using, embarrassingly enough, Infopath.
Then again, faced with the limitations, I've been fighting to learn every possible way that our globally deployed Excel workbooks might interact with Sharepoint. It's crazy...every environment has its own unique mixture of what is allowed and what perceptions there are about stuff.
I think you're right, SQL Server is SP backbone. But how 'open' things are is all up to your Sharepoint Admins (I call them SP Gods). Mine don't even have Workflows turned on...