I wonder if anyone working on that first show had any idea people would still be watching it over five decades later? Probably not.
I became a casual fan of the show back in the Tom Baker days (as did most Americans). I REALLY got into the revived series though, which premiered in 2005. I loved David Tennant's performance, as I think his Doctor may be my all-time favorite (sorry, Tom!).
It's just too bad the show ended with the 2017 Christmas Special. I miss it already, and I hope someone at the BBC decides to revive it a second time soon.