> It seems increasingly common these days to not worry about performance at all,

You don't even have to continue there. People, who should know better, assume that 'modern cloud stuff' will make this trivial. You just add some auto-scaling and it can handle anything. Until it grinds to a halt because it cannot scale beyond bottlenecks (relational database most likely) or the credit card is empty trying to pull in more resources beyond the ridiculous amount that were already being used for the (relatively) tiny amount of users.

This will only get worse as people generally use the 'premature optimization' (delivering software for launch is not premature!) and 'people are more expensive than more servers' (no they are not with some actual traffic and O(n^2) performing crap) as excuse to not even try to understand this anymore. Same with storage space; with NoSQL, there are terabytes of data growing out of nowhere because 'we don't care as it works and it's 'fast' to market, again 'programmers are more expensive than more hardware!'). Just run a script to fire up 500 aws instances backed by Dynamo and fall asleep.

I am not so worried about premature optimization ; I am more worried about never optimization. And at that; i'm really worried about my (mostly younger) colleagues simply not caring because they believe it's a waste of time.

There's also something to be said for building better tooling in this area. Not everyone can achieve expertise in everything. Better tooling helps level the playing feel (& eventually outperform experts when the tooling becomes indispensable).

You may think that's a cop-out, but consider something like coz[1]. Sqlite is managed and maintained by experts. There's significant capital behind investing engineering effort. However, better tooling still managed to locate 25% of performance improvement[2] & even 9% in memcached. Even experts have their limits & of course these tools require expertise so a tool like coz is still an expert-only tool. The successful evolution of the underlying concept for mass adoption will happen when it's possible to convert "expert speak" into something that can be easily and simply communicated outside CPU or compiler experts to meet the user on their knowledge level so they can dig in as deep as they need to/want to.

[1] https://github.com/plasma-umass/coz [2] https://arxiv.org/abs/1608.03676