There's also the "React is the industry standard that tons of developers and companies use" vs. the "WebComponents is the 'official' standard that nearly nobody uses".
Yes, I'm being hyperbolic. But if you're worried about longevity I would certainly hitch my wagon to React before I hitched it to WebComponents.
Unfortunately I don’t think that comparison quite holds. jQuery is mentioned less and less because core browser APIs implemented a lot of what it does and made it unnecessary.
Even if Web Components solve the “create a component” part of React there’s still an absolute ton of stuff it provides that Web Components don’t. I tend to think of WC as a low level API you want a library interfacing with rather than your own code, e.g. the way Svelte exports web components.
If it's a choice between removing the JQuery dependency from old JQuery code, or updating equally old vanilla javascript, I'm going to be picking the first option a lot.
Yes, I'm being hyperbolic. But if you're worried about longevity I would certainly hitch my wagon to React before I hitched it to WebComponents.