Is it possible that Bitcoin could increase its total supply in the future?
Any tamper on the total amount of Bitcoin would be a red flag because it would raise a lot of questions about the nature of Bitcoin that we've trusted over the years, and people would be interested to know who increased the supply and to know if it is really free from control.
And in my opinion speculating about any further than that is wrong because of the way technology advances, we may have something far better than Bitcoin 20 years from now.
This is a fact.
@OP, worry about now; leave worry about the future for later.
Yeah, as it was said, there is no incentive to get a bigger total amount - it would destroy the hard cap that has been set and trust would go lower than ever for BTC, which would be the worst scenario for the crypto space in general, in my opinion.