I say this as someone who isn’t very familiar with this world, but have also noticed this. I think it’s a perception hack: there are some expectations about how a series A startup operates (demonstrated product/market fit, starts entering the growth stage, etc), and investors/founders still want to invest in companies that show great potential according to them, but just aren’t there yet, and it’s undesirable to oversell the company / raise expectations too high.

Hence the massive seed rounds, with equally massive bridge rounds, etc etc.