> I've rarely seen a need for a front-end framework. I know that sounds like heresy.
No it sounds like the comments on every post on HN remotely related to JS.
> I've never bothered to learn Angular, React, NextJS, Svelte or any of the alphabet soup named frameworks
That makes your opinion definitionally uninformed. If you had bothered to learn any of them, you would see that they have many benefits. Nobody is saying that you need any of them, but they are very useful.
The single greatest advantage to using any of the frameworks, however, is that they provide a relatively definitive way of solving any of the problems that you will have to solve, building an SPA. Routing, caching, state management, reactivity, inputs...There is no way around solving these problems, so you're either going with what they've got, or reinventing the wheel. But by reinventing the wheel, you're probably going to do a worse job than the team that has spent years solving these problems, and more importantly, you're losing access to a definitive way of doing things that you (and others) can refer to.
And that's the real kicker, is working with others. I worked as a contractor for years, and I can tell you the ease of jumping on a project using a front end framework vs a home baked JQuery or vanilla solution was practically immeasurably vast. Even jumping on a project using a framework I'd never heard of, but still had documentation and an online community, would have me up and running within a day or two at most.