Oh boy, not those radical beatles-fans again ;-)
Sorry, just kidding, back to topic:
I agree with you, that the Beatles is one of the greatest bands in history. I also don't want to compare Beatles with Coldplay, that's simply not possible, two different centuries, two different styles, two etc. ...
Theres another thing I want to talk about, you wrote:
I think, that's not true. Especially during the time right after the Beatles, 60s, 70s, 80s there were some bands, making a masterpiece after another. For example Pink Floyd: Dark Side Of The Moon (1973) - Wish You Were Here (1975) - Animals (1977) - The Wall (1979). These four albums were great commercial successes, compared to the other ones made by the Floyds (although I have to say, commercial succes is not equal to quality). They only took more time to make these LPs, because they were much more complex than the ones from the Beatles.
So, I think, as time passes by, you can't say, that old bands after 40, 50 years are still the best (of course they are for you!), what do you think does everybody think in 70, 80, maybe 100 years, when everybody, who heard the Beatles "live", is dead? I don't think, that they'll be the best band ever anymore in that time.
Just my thoughts on that.