When people talk about "scalable" systems, it's usually a misnomer. Most enterprise software doesn't really scale. It simply assumes large deployments and makes every user jump through the hoops that make those deployment possible. In fact, the most common use of the word "scalability" I see in practise is as an excuse for something being hard to operate and consuming too many resources.
Truly scalable software is different. It scales in both directions, up and down. It can be used for a weekend hobby project or for an "enterprise" system. With such software you "pay" the complexity cost only for features you actually use. Software of this kind exists, but it is exceedingly rare.