I find the complexity graphs to be a little misleading. If the client side complexity grows, but server side complexity doesn't decrease at all, then something has gone wrong.
If you have a fully client-rendered SPA (not saying an SPA is the only thing you should ever build, but many of the complaints seem to be aimed SPAs), then why do you still need Models, Controllers, and Views on the server? Or Routing for that matter. Many modernish SPAs would handle all the routing client side. So your backend complexity might look more like:
Asset Packing, API, Authorization, Dependencies
So you've moved some of the complexity from the server to the client. You may or may not like that, and there may still be a net increase in overall complexity, but it's not the same as necessarily suddenly 2x complexity.
Also I don't know what Authorization is doing in both graphs. Or why Virtual DOM is there - yes you might be using a Virtual DOM, but it's presumably part of one of your dependencies, and not something you're interacting with directly or maintaining. Also what is a "Controller" in React? React (and similar frameworks) don't fit neatly into the MVC paradigm. I guess it's more like Components + Models? Although the Components aren't always cleanly separated from Models/business logic, which can be a strength and a weakness.
If you have a fully client-rendered SPA (not saying an SPA is the only thing you should ever build, but many of the complaints seem to be aimed SPAs), then why do you still need Models, Controllers, and Views on the server? Or Routing for that matter. Many modernish SPAs would handle all the routing client side. So your backend complexity might look more like: Asset Packing, API, Authorization, Dependencies
So you've moved some of the complexity from the server to the client. You may or may not like that, and there may still be a net increase in overall complexity, but it's not the same as necessarily suddenly 2x complexity.
Also I don't know what Authorization is doing in both graphs. Or why Virtual DOM is there - yes you might be using a Virtual DOM, but it's presumably part of one of your dependencies, and not something you're interacting with directly or maintaining. Also what is a "Controller" in React? React (and similar frameworks) don't fit neatly into the MVC paradigm. I guess it's more like Components + Models? Although the Components aren't always cleanly separated from Models/business logic, which can be a strength and a weakness.