Obviously popularity doesn't always equate to quality, but given that The Scientist on Spotify is Coldplay's second most popular song at over a billion streams they've got to be doing something right there.

Making more repetitive, less dynamic songs makes them more palatable to a wider audience (i.e. accessible)

What they did right, in my opinion, was making a pretty melody over a classic pop progression. But I think they could’ve made a much nicer, more loving song if they had continued writing it.

But you’re right, they kept it simple to likely sell more copies and I don’t blame them. I’m just disappointed in them because they wrote something really nice and left it without continuing.