The thing is, interpreted languages have a natural advantage vs. more performant, compiled ones when it comes to iteration speed (and also often ease of early deployment). I think the reason we see this is that while it would be great to pick a more performant language at the beginning, it may mean that your iteration speed is too slow and you simply don't survive as a company (run out of funding, can't pivot fast enough, etc.) In my mind, it's actually a very reasonable choice to start with what you think will be the most optimized for early developer productivity. Once you get to be a company worth tens of billions, you can just pay people to solve this problem for you.