Databases will love Optane. There have been companies showing how much they are willing to spend on database hardware and software for ages. I'm not sure that will change any time soon.
Not so sure about this. World is increasingly moving to distributed scale out databases. Once you go that way consensus algorithms and rpc costs dwarf disk io speed.
Not everyone is building apps which need to be "web scale". Optane has the potential to significantly raise the performance ceiling of a single-master database. I bet there are a lot of companies who will happily drop six figures on Optane systems if it saves them the complexity of managing a distributed database.
The niche where your present requirements are big enough to benefit from Optane and your future requirements are small enough to not need to go distributed is pretty narrow.
I've worked for a company that was willing to spend that kind of money on monolithic database servers. They were a top-100 website though, and this was the best part of a decade ago (and thus e.g. in the pre-SSD era).
They were also scrambling to move all their services away from use of that database in favour of a horizontally scaled system that could grow further.
The query rate that can be handled by a single conventional server are pretty monstrous these days. You'd have to be simultaneously a) maybe top-50 website level load (I'm well aware that there's a lot more than websites out there, but at the same time there really aren't that many organizations working at that scale, much as there are many that think they are) and b) confident that you weren't going to grow much.
Yep, exactly what I was getting at. If you have a giant database and a big budget, Optane is great. It could be really useful for smaller users too, but its unlikely to become widely popular as the average developer won't have it available in their laptop or desktop.