So where should the tubes be?

In the 50's and 60's were they were the best we could do.

… and in 2021, tubes are still the best we can do. 

i have tubes in my speakers... 🙊🙊🙊🙊🙊

Just lurking and learning. Why do the number of tubes in a component vary so greatly? 

#of tubes? Depends on what the amp is doing and how it’s configured. A power amp could have a single power tube (SET) or it could have 8 paralleled push-pull output tubes. A phono amp could have only 2 tubes for gain and equalization or it could have an output buffer, tube regulators and rectifiers etc. You can see the 11 tubes in my phono amp here