Look at it from the startup's side of things: The ideal office that we'd all love to work in - that perfect 4-6 person bullpen with private offices surrounding (x number of 4-6 person teams), is _expensive_. Very few companies can afford a build-out like this until much much later in company-life.
If we're talking about an Apple or Google, fine - let's have the debate. But for a vast majority of early-stage startups, this simply isn't a viable discussion to have. Office space is very limited in many parts of the big tech hubs, and often it's a matter of just getting an affordable space in the first place, much less being able to build out the perfect working environment. And the fact of the matter is, most spaces are open and filled with $200 IKEA tables because that's all the company can afford.
So I'm not sure what the answer is. On the one hand, you can say "well, budget more for office space", but we all know it's not that easy. It's not a small expense -- big buildouts for private offices costs tens of thousands of dollars (or more), precious capital for a small business.