[Nursie]

Yes, the difficulty rebalances periodically (every two weeks, roughly?), it would take a catastrophic decrease in hashing power to affect that by too much.

The mining reward stays the same, though it drops by half every few years (one such drop is approaching in May).

The network actually becomes non-functional for low transfers the other way - when there's too much interest, and too many transactions, the fees to get a transaction through start to rocket. At the peak of the 2017 hype the y hit around $50-70, IIRC.

[foepys]

It balances after 2016 blocks, not 2 weeks. This is a crucial difference because when the hash rate drops dramatically, those 2016 blocks might take 4 or even more weeks to create.

[Nursie]

Yes, it could. There is a hypothetical "stuck network" situation, but that really is dependent on a lot of network power disappearing. Before that you'd end up with a lot of idle hash power and ex-miners wondering what they could achieve in the way of an attack with it...