Back when trains WERE trains (and you could still get change for a threepenny bit), Duchesses were replaced by soulless heaps of junk called English Electric Type 4s. Ugly, smelly and not a patch on what they replaced. Today, some even claim to love them, as Class 40s. They, in turn, were replaced on the prime runs (the Duchesses' stamping ground) with Brush Type 4s, which looked well-styled and modern, and, if lucky, stuck in the memory for being frequently seen in a bright pink livery (that's another story). Moved away from Duchess territory, but the Brush 4s were still around. Not much changed (we'll pass over the aberration that was the other EE Type 4s, the Class 50). The HSTs, though they took over the Brush passenger work still left them enough to do, and were an entirely different concept anyway, so I could grow to like them. Preferred them to the EE Type 5s, which were East Coast wrecks, flash monkey types. Don't really get on with the 91s, though.
Apart from revealing that I don't really like English Electric locomotives*, what i am trying to say is that you form an irrational attachment to one type, hate its replacement, love
its replacement, and so on. And enthusiasm will continue as types come and go
* I do have a soft spot for the Type 3s, but the Type 1s always were inferior to the Brush 2s
