The choices were clearly (far) less important than having the best model and a good product that was way ahead of the competition.

However, that's not the same as the technology choices not mattering at all. As others have mentioned the product is buggy, and it appears Anthropic are struggling to continue to release new features within the existing architecture.

That's also not to say that Anthropic made bad choices - there's always going to be a tension between building quickly to capture the market now vs moving slower and building something more maintainable in the long-term.