There's also much more technical pressure on a greenfield project mainly because if it turns bad it's "your fault". There's no legacy to blame, no excusing bad

There's also much more technical pressure on a greenfield project mainly because if it turns bad it's "your fault". There's no legacy to blame, no excusing bad choices (you made them!). It is part of the responsability but if and when it goes sour there's a bigger feeling of impostor syndrome than on a legacy project.