The doors were lauded at the time, they were the first American band ever to have eight consecutive gold/platinum albums.
They weren't that big here. They sold just under 5 million albums and 7 million singles in the USA in their whole career.The Beatles used to do that every quarter.
'Their whole career' is rather misleading, considering they were only active for four years and compared to The Beatles, every bands record sales were poor.
If you are only counting their recording years with Jim Morrison then they were active for half as long as the Beatles. But didn't have half the sales. Same with Oasis, who in 18 years sold a tiny fraction of what the Beatles did in less than half that period. As someone around at the time the Doors weren't big in this country in comparison to numerous other bands. The Melody Maker and NME writers, especially the pretentious ones, got excited by them but they weren't on the general radar. Anyone riding about on Lambretta back then would have been more into Genocide Washington, Action, Creation, Alan Brown Set. Bands whose records you don't hear at Mod Revival gatherings.
Those (Mod) bands were surely a good bit earlier than The Doors? 2-3 years, which is/was a long time in Pop. Different market too.
As I said, compared to The Beatles, every bands sales were ****, that doesn't mean they weren't highly regarded at the time. And you said they were highly regarded after the event, not at the time, nobody mentioned it being just about what people in Britain thought. The Doors were so influential at the time, that there was even a daft conspiracy theory that the CIA killed Jim Morrison because of his massive influence over the youth of America and the potential effect on their drug taking.
Morrison was a good advert as to why drugs are not a good idea. As were many others of course. The sad fact is that this once good-looking chap (almost too good-looking as they said in one famous Pete and Dud sketch) was at 27 a bloated wreck. Delusions of grandeur and megalomania didn't help of course. His time on earth , like Brian Jones, Jimi Hendrix and Janis Joplin who all departed this mortal coil at the same age was never destination ed to be long. Which in a lot of ways what rocks stars should do. Then you remember them at their prime, not parodies of themselves so many later become.