Security, scaling of development, and progression of language features. The larger a code base gets, the more complex it can be, and frameworks help abstract i

Security, scaling of development, and progression of language features. The larger a code base gets, the more complex it can be, and frameworks help abstract ideas (like design systems), rather than having to repeat component code, css, each time it is needed. Also, if more developers are being added to the code base, the scaling of a project can get quite large. We have over 50 developers working at my company coding on the website. Security is another. When updating a list of items (for example) from a fetch, vanilla js will require direct modification of the html, whereas a framework like React will handle that, with best security practices applied, as the code has been written and production tested. I'm not going to deep dive on language features, can be quite subjective, for example how great Typescript is (compiler errors > runtime errors), or how SASS fills in a lot of missing features for CSS, etc. I think some websites could be done in vanilla JS/HTML/CSS, but as the site scales, I feel at some point a developer would build their own framework to make things easier and streamlined. It's what developers do.