Google is basically split into "build things that make users happy" teams and "build things that make Google money" teams, so I think that on an individual product level you may be correct, but in aggregate at the high level Google believes there is a ton of value in revenue-less products.

Now for Podcasts (or any given product) there's always going to be some calculus of "is it enough value to justify the cost", and clearly Google believes the answer here is no.