With the web platform everything is sat on top of shifting sand ... i.e. changing browsers, standards and devices. Almost nothing in the tech world has changed so fast over the last 15 years than the software and devices web platform code is expected to run on. I'd say that given that churn, the quality of modern web languages and tooling is remarkable.
Writing backends vs frontends is a totally different thing. Backends tend to run in stable environments, and mainly you concern yourself with data in and data out. That's not to say its easy, there can certainly be be plenty of "essential complexity", and infrastructure and scaling is a whole additional set of concerns. Frontend by contrast is a much more fuzzy issue, clients need to run across many unstable environments and require skills very far from traditional programming - sensitivity to design, UX and animation for example. If you're good at backend, it doesn't mean you're going to enjoy frontend too. And if you don't enjoy frontend it doesn't mean all the frontend tech is "bad".