Non-constructive reply: Developers have been burned too many times by snake oil vendors and "solutions" that only work for toy examples. Also, I've never seen being slow to be encouraged anywhere. Most consider it an acceptable tradeoff though.

Constructive reply: What would be an approach to writing a large web frontend (large as in, many pages and controls) without using a large framework?

I'm asking this because I know how to do it in React but also how to do it "the old jQuery way" (or equivalently, using today's standardized builtins). Productivity is easily 100x larger with React.

edit: Ideally, together with a link to an example open-source application that does it that way, to understand how it works and feels at (code) scale.