What happens to the Bitcoin when it maximizes its 21M capacity?

With Bitcoin becoming more difficult to mine by the day, and requiring more sophisticated equipment to keep up with rewards, can it survive the end of mining profits?

https://news.bitcoin.com/what-happens-bitcoin-miners-all-coins-mined/

As it stands, the transaction time for a bitcoin transfer is 10 minutes to 3 HOURS (if the transaction does not get dropped entirely for lack of resources). Transaction fees are an incentive for miners to process blocks, but does the supply and demand curve support a stable network?

This broaches some questions;
Will there be a mass "Panic Sell" as the Bitcoin Supply runs out?
Will Bitcoin suddenly increase in value due to scarcity?
Will transaction fees (or times) kill the Bitcoin?

Although the predicted end of the curve is in 2040, with increased interest in crypto-currency this could be accelerated to anytime between 2020 and 2040. Are investors anticipating a crash and planning to sell to uninformed buyers through growth propoganda? Or, will Bitcoin be a stable and immutable continuing currency?

I'd love to hear your thoughts!