For-profit companies typically build toward what they believe is in-demand and will be well-received by consumers. They perform market analysis to reinforce their intuition. Sometimes they get it right and their stock goes up.
There isn't some elaborate plot on the part of Google, nor are 'they' purposely making something 'no consumer ever demanded.' When they do this, the endeavor fails and we call it a flop.
They never show an actually alternative version. A/B or bandit testing doesn't cover a comparison between, say, a nicely designed, very fast, non-tracking, but less interactive version, or a slow, but full-fledged "app".
There used to be mobile versions accessible from desktop (twitter, facebook, etc), but not any more without faking the user agent. Those are significantly lighter, than desktop versions, but there is no way to actually compare the two for the generic public, and companies don't seem to be brave enough to really dig into these questions.
This is the comparison I miss.
Hence my wording: assumption.