This is not true for all startups and all kinds of businesses. May be for some, but not for all. There can be a lot of differences in the nature of work being done between different team members even in a small team of 5.

The best example I can give is of myself. I once got appointed as the social media manager in an e-commerce company who just had a single room office, and another smaller room for some of the product that had to be shipped out regularly. I found it disgustingly hard to work because as a content writer I was desperately craving for peace and quiet amongst all the chatter so that I could come up with new article ideas and social media campaigns. I was forced to work from the very same table where the founder, the logistics guy and the sales guy also worked. We were just a team of 4.

It was as distracting as the open plan office of any larger company. The founder kept chatting with the sales and logistics guys all day long, and I just couldn't concentrate on what I had to deliver that day. The founder was also on his phone for the rest of the time. Luckily, the covid -19 pandemic struck and that allowed me to work from home for the next 6 months. But when they called me back, I never went.