It had many hardware upgrades over the years - upgraded CPUs, 128GB RAM, 4TB NVME storage, a modern AMD GPU, USB3/c, thunderbolt, etc
The only reason it got replaced is because it became too much of a PITA to keep modern OSX running on it (via OCLP)
Replaced with an M4 Max Mac Studio, which is a nice and faster machine but with no ability to upgrade anything and much worse hardware resale value on M-series I'll have to replace it in 2-3 years
Yes you can still update to 15.7.3 the usual way in Settings
It'll present you the Tahoe upgrade but underneath in small print it'll show other updates, which you have to then open and manually select the 15.7.3 update
And you really should keep up on the point updates because there's been a ton of major security patches since 15.4
What you call scaling up sounds more like monetization. Others (especially customers) might call it enshittification instead. Youtube is a great example of how bad it can get.
Why Mozilla won't let people financially contribute directly to Firefox development and continues to pursue these stupid monetization paths is a mystery.
HN hasn't focused on those topics in a long time, they rarely are on the front page. Skip the top 20 articles and you'll start to see some interesting content instead of all the VC & AI drivel.
Hackaday is a content aggregator site that usually has more content on these topics - https://hackaday.com
Possibly the most common open source mailing list software, mailman, has had configuration options to address both email address and header exposure for at least 15 years
At least with email, you're in control of what shows up in your inbox as well as message routing with filters of your choice
Amazon has been doing it with Firecracker for a while and Kata containers is another popular one
https://github.com/firecracker-microvm/firecracker
https://github.com/kata-containers/kata-containers