Curious about Bitcoin's future, vanishing coins & the mining challenge

Hey folks, I've been questioning myself about Bitcoin in the long run. You know how the total supply is capped at 21 million, right? So, what happens when bits of that supply start vanishing into thin air because some users lose access to their wallets (like, say, someone forgets their password or, sadly, the wallet owner passes away without leaving access info)? Over time, won't we end up with a lot less Bitcoin actually circulating?

And then there's the whole mining gig. With the rewards for mining a block getting halved roughly every four years, how's mining going to stay profitable and worth the effort, especially as we get closer to the last Bitcoin being mined? I mean, if the rewards keep shrinking, but the costs (like electricity and hardware) don't, won't that shake things up?

Just tossing this out there to see if anyone else is pondering the long game for Bitcoin and how it's all going to work out. thoughts?