I guess such a service gets coupled too strongly to that platform, and major engineering effort is required to deploy it the old-school way.

I left Google in 2022, but I remember seeing the beginning of this. The system that got built up to do all the things Google wanted to do -- previously "simple" things, orchestrated on raw hosting (Borg) -- got too big and complex. (Partially because it was too flexible, so too many projects did too many unique things, and running them grew difficult to match.) So they started adding abstraction layers, to make it "simpler". (Which as always means the common/easy case got easier, and the rare/difficult case got harder. The team I was on at the time couldn't use the new thing for (most) of what we did, because our needs were incompatible. But we did enough other compatible things that I started learning about it/using it.)

(Personally I'm sure it's doomed to failure. But partially because most all technology operates in cycles/like a pendulum. The abstraction layers will grow too onerous and limiting, and the solution will be to dive closer to the metal again.)