I would not have bought the car if not for FSD. And I know my friend bought it for the same reason. And I didn’t expect it to work for 4-5 years and I know it will have limitations when it does.
It's not clear whether Tesla would be able to survive without differentiating themselves enough without leading disruptive technologies, like FSD. This is part of Tesla's charm - the fact that the car gets better and better. If it were just a fun car to drive and nothing else, they'd be in a world of competition head-on. Safety, driveability, energy storage and distribution, technology and anticipation of software enhancements is part of their winning strategy and its put them ahead. To the degree they stay ahead is an unknown, but with the sheer volume of data they've collected for building FSD, they're well positioned to continue in the leading position for the next few years. After that is anyones best guess.
That said, Elon must have something up his sleeve that he hasn't shared with us and I'm hoping that we'll finally get a glimpse of later this month during the Autonomy Investor Day (on Apr 19th). The expectation is that it is going to be something entirely different from what we've got now with Enhanced AutoPilot/AutoSteering - and it would need to be if its going to do what Elon claims - namely "It’s there for when we start competing with Uber/Lyft & people allow their car to earn money for them as part of the Tesla shared autonomy fleet." This is clearly a huge leap from what we've got our hands on now.