True, but with two guitars, two drummers and a keyboarder, there was a bit more going on as regards musical colors. It was also a more gentle breeze improvisation, Cream was more intense in a sometimes exhausting way.
Sting once said something very perceptive about the demise of The Police: He said it that it became like painting from a color palette with always only three colors, no matter what you did. And that he wanted the availability of more colors to flesh out the songs he was hearing in his head. In Police, he had a greatly versatile guitarist and a totally idiosyncratic, gifted drummer, but it was still always the same colors.
Much as I like the charm and freedom of trio music, I can relate to that. Cream, Jimi Hendrix Experience, early Grand Funk Railroad (sans extra keyboards), Taste/early and late Rory Gallagher (ditto), Trapeze, Robin Trower Band, ZZ Top, Rush, even King Crimson in the RED era or UK (in Jobson/Wetton/Bozzio line-up) - none of them sounded really varied in musical colors. Not in a way a band like, say, The Beatles (with George Martin as the fifth Beatle) or Queen did.
Clapton moving on from Cream had a lot to do with that - it wasn't just having heard The Band's songwriting, but also the infinite musical colors The Band could produce (largely thanks to Richard Manuel and Garth Hudson). He never returned to a three-piece-line-up and is tellingly one of the few guitar gods that would nearly always want a second guitarist with him. I believe to him "trio rock" had become a somewhat adolescent concept - discuss!
Police became actually quite a bit of an "orchestra" in the studio with the later albums - Zenyatta Mondatta was really their last sparse album (though not as sparse as the first two) -, but not sparse enough for Sting's ambitions obviously.
I've played in trios myself. And because I'm a busy and melodic/harmonic bassist with a penchant for doing things on bass most people don't do, I believe I was rather good at it, at least that is what people told me who played with me. But for all the intensity and fun of it, I sometimes missed additional musical colors too.
These days, I find any band line up I play in that doesn't also feature a keyboarder (who plays a lot and not just backing!)
amputated.
I find the sonics of the early 70ies Elton John Band more attractive than those of the Jimi Hendrix Experience, now stone
free me! There must be a closet pianist/organist lurking in me.