This is because you are looking only at provisioning/deployment. And you are right -- node size does not impact DevOps all that much.
I am looking at the solution space available to the engineers who write the software that ultimately gets deployed on the nodes. And that solution space is different when the nodes have 10x the capability. Yes, cloud providers have tons of aggregate capability. But designing software to run on a fleet of small machines is very different from accomplishing the same tasks on a single large machine.
It would not be controversial to suggest that targeting code at an Apple Watch or Raspberry Pi imposes constraints on developers that do not exist when targeting desktops. I am saying the same dynamic now applies to targeting cloud providers.
This isn't to say there's a single best solution for everything. But there are tradeoffs that are now always apparent. The art is knowing when it makes sense to pay the Cloud Tax, and whether to go 100% Cloud vs some proportion of dedicated.