Few things. About #1 there's Win32 API, MFC, WinForms, GTK, Qt, Swing and all do UI and thousands of applications are built with far more state and complex UIs

Few things. About #1 there's Win32 API, MFC, WinForms, GTK, Qt, Swing and all do UI and thousands of applications are built with far more state and complex UIs than a normal SaaS, price comparison portal or a booking website ever could imagine - but none of those technologies are ascomplex, as bloated and as fragile as modern frontend stack has become. Second - Backend complexity, Kubernetes isn't Backend precisely, async Queues are unavoidable but these Microservices are basically an anti pattern driven by greed to land the next Job and hence insistence on using different programming languages per team/indivual etc. Now a cottage industry in it's own right with it's own self proclaimed scholars whereas it is just and exactly the domain of distributed system already. If that constraint of per team programming language of choice is removed or languages interoperate with zero configuration, 98% of the companies need just well maintained internal libraries.