2.4Ghz is still very much in use in many places. I will use it even though I have dual band a lot due to range/penetration limitations.

I have recent stories from friends whose apartment microwave will cause internet issues.

You would be surprised that most wifis out there still don't run on 5ghz. I mean what do you expect from non-technical people, wifi is just this white box that should work, if not turn off/on and then call support. Ie we (Switzerland) have both bands available from the router and till now even I didn't know that higher band is better for interference, and I am most technical in the family/friends circle.

5Ghz also has drawbacks. Routers support both, usually with an option to either combine them and handle the selection automagically or separate them. Parent is just wrong about routers having switched over completely - and thus the microwave can indeed still be a problem.

It's your neighbors, ALL OF THEM, trying to watch 4K on 2 TVs per household all at once.

And why shouldn't they? That's like the whole reason to even have a high-bandwidth internet connection.

They should - but hard-line Ethernet connected.

2.4Ghz is still very much in use in many places. I have recent stories from friends whose apartment microwave will cause internet issues.

Yes there's plenty of reasons, channel saturation, low quality routers, various interferences. My Ethernet cable is easier to debug.