I'm pointing out that this particular pattern (Server Components) is engendering more complexity than necessary.
If you have a full blown SPA on the client side, you shouldn't use ViewModels as that will ties your backend API to the client. If you go for a mixed approach, then your presentation layer is on the server and it's not an API.
HTMX is cognizant of this fact. What it adds are useful and nice abstractions on the basis that the interface is constructed on one end and used on the other. RSC is a complex solution for a simple problem.
Note “instead of replacing your existing REST API, you can add…”. It’s a thing people do these days! Recognizing the need for this layer has plenty of benefits.
As for HTMX, I know you might disagree, but I think it’s actually very similar in spirit to RSC. I do like it. Directives are like very limited Client components, server partials of your choice are like very limited Server components. It’s a good way to get a feel for the model.
If it is new to the DOM it will get added. If it is present in the DOM (based on id and other attributes when the id is not present) it will not get recreated. It may be left alone or it may have its attributes merged. There are a ton of edge cases though, which is why there is no native DOM diffing yet.
If you have a full blown SPA on the client side, you shouldn't use ViewModels as that will ties your backend API to the client. If you go for a mixed approach, then your presentation layer is on the server and it's not an API.
HTMX is cognizant of this fact. What it adds are useful and nice abstractions on the basis that the interface is constructed on one end and used on the other. RSC is a complex solution for a simple problem.