the rewards will get smaller, but even if the rewards are small in the future, a bitcoin will be much more valuable than today (if everything goes as "planned").
This is a very false thought. The whole system shouldn't rely on the belief that it'll have a greater value in the future. It's important to know what will happen if the value remained the same.
well, you will not know until it happens - and imo it is highly
unlikely the value will remain the same
every system "relies" on the unpredictable future