I think it’s gotten a whole lot simpler in the past 10 years. People used to have to rack their own hardware, install PDUs, check temperature gauges, plug wires, configure the switches, setup RAID and backups, make sure you have that serial cable plugged in so you can telnet in in case the switches don’t work, and lock the data center doors without forgetting their keys back in the day. And this is before actually developing and deploying your application software.
Now you can just buy a bunch of db cycles and scale to >10000 qps without batting an eye (though you’ve got to watch your wallet).
I think because some of the hard stuff got a lot easier, the easier stuff got unnecessarily complex. And there are so many ways to scale things that some of these constructs and idioms used over time stopped being used because they mattered less if you could just turn a knob to scale your crappy code.