Yes; regulators are scarce too. The old LM2936 is disappearing from stocks, unless you buy the version with the enable pin (which far fewer people want) and buy it from Mouser (who charge more than anybody else - how the hell did they become one of the very few TI distributors in the UK??). The MIC5201-5.0YM-TR has the same pinout but the enable pin works backwards, which matters if you are using a 2936 with the enable pin. But there are loads of regulators...
I don't really agree that old components are not used/usable anymore. The 1N4007 of decades ago is now SMT and might be a BYG10M or one of dozens of equivalents. So if an LM358 does the job, use that!
Choosing components, using old ones as far as possible, is an art, which few people have unless they have been at it for a long time and preferably have been responsible for their own company. But if you do it right, you eliminate 99% of headaches.
What has happened, over past few decades, is that manufacturers have focused on unusual parts, with some unusual feature, to entrap less experienced designers into designing-in unusual parts. That's where the money is. It is not in LM358s, or BYG10Ms.
ST are successful because they deliver good value. They do lots of cheap chips. Look at the STLED316 display driver. €0.75 1k+ and that's from Mouser which is always expensive. You get a driver for 6 digits for that. They also do loads of less well known op-amps, comparators and such like. And the 1k price for the 32F417 is about £5.