Many other professions factor in distractions in their office space set up. I don't think I've been to a decent attorney or CPA office setup where they were in a shared space or hotdesk situation. Offices layouts can definitely be built for this approach - perhaps you're just noting that nothing's available? Or nothing's available at a price management wants to pay?
> If you want to redraw the floorplan, you have to sign rental contracts upwards of 5 years, something no sensible startup would do ...
If it was a nicely done space, I've little doubt the space owner would have trouble leasing it out again, either to one large org, or to smaller orgs who all want private space. I run a coworking space, and most people who contact me are still really just looking for individual office space.