This works up to a point. Past a certain scale, running a database becomes hard(er), and you also start to need proxies, caches, load balancers, etc. to maintain performance.
I would agree, though, that many software installations never need to scale to that point. Perhaps most.
At what point do you hit that scale with project management software, though? Maybe you can't get to the point where you're managing all projects across all of Walmart from the same instance, but certainly you can run pretty much anything of reasonable size.
I would agree, though, that many software installations never need to scale to that point. Perhaps most.