Even if you had a high degree of confidence that would happen eventually (which I'm not convinced you do), such a play would be absurdly risky, especially given no idea as to the timing.
I used the word "legitimate" because the parent to my post did. The way I see it there is nothing legitimate about any of these so-called currencies. They are probably all Ponzi schemes in the end.
There’s also the block reward halving process, which is separate, but in theory miners will still be incentivized to mine even after it hits 0, due to transaction fees. If not, well, the difficulty will go down until they are.
You don't even understand how mining difficulty works.