It gets increasingly difficult to design a website properly when you have different teams with different goals each competing to put their little feature front-and-centre, leading to a hacky job on top of a hacky job on top of a hacky job, which in turn hurts the performance until one day someone finally decides to re-think the whole thing from scratch and pisses off >50% of its users in the process that are used to the mess.

It's way easier to nail the UX when you're still in the dozens-of-employees stage of growth and offer like five features in total.