I would say something quantum resistant, but even that exists already. I don't think the problem is so much the coin, but rather the usecase. I see most businesses and governments launching and running their own chains in the future. So rather than launching a coin, launching a business that helped people launch their own chains would be the way.

If it becomes sufficiently unprofitable to mine LTC does it just die? I mean, does the chain just stop producing blocks? I thought there was difficulty adjustments to make up for stuff like this.

In agreement with most of the above. But with a twist. It's kind of interesting to see how the networks are kind of maturing. Solana really owns the memecoin space rn. ETH did for the longest time, but with txn costs and age it's almost achieved a boomer kind of status in many eyes. Almost like it's the S&P or something. Anyway, point being it seems like the different chains are finally starting to accept their own roles/niches instead of working so hard to port everything into themselves (think ordinals). I just don't think having an entire other chain built on memecoins is really going to accrue value bc that's basically what solana is already.

At least people are still looking at novel ways to secure networks though.