It doesn't matter if someone, or a group of people, spent years researching a topic: even given an extremely similar situation with similar resources and constraints, an engineer right out of school will still feel compelled to try and solve the problem anew.
Part of the issue is that we're very bad at identifying constraints and context, and thus it's really hard to apply pre-existing solutions. Eg: people trying to apply concepts developed by large FAANG-style companies in a startup.
Part of it though, is sheer arrogance. Everyone feel like they know better. There's also a bit of "playing programmer" going on: folks do a lot of things because they find them more fun, even if it was somehow objectively a worse solution (and they knew it). Because software engineers are in such high demand, people above are afraid to drop the hammer. Concept such as team or individual autonomy are put above the global maximum of the business. This autonomy and freedom is justified by saying it drives innovation, but you're not innovating if you're constantly starting over. For example, while modern languages do have some cool new features, we also keep reinventing the tooling, editors and debuggers around them, which drives progress in those areas to a crawl.
All around, there's a balance between solidifying some concepts, vs continuing to innovate. Right now we're leaning a bit too hard toward chaos, and the industry would benefit a little from letting things mature.