Some early tech decisions matter, but most don't matter as much as people think they do. Other than the OS, I haven't really seen it be a complete deal breaker

Some early tech decisions matter, but most don't matter as much as people think they do. Other than the OS, I haven't really seen it be a complete deal breaker for anyone that's willing to put in the work in the first five years. Postgres not handling things well? Slow migration to DynamoDB or to sharding. Python falling over? Roll the hot codepaths in Cython or horizontally scale. Node doesn't have great data science libraries? No worries, build a couple of small python data science services and get on with life. The only reason I think the OS choice matters at all is because I've never seen someone move from .NET on Windows to Linux or visa versa. Could be done, but people generally don't do it. So your hiring pool is going to look different. Generally more scrapy on the linux side, generally more careful on the Windows side, but even there that's mostly about culture and priorities. Both stacks can handle basically anything.