While I'm in no position to say with any certainty whether 640 KB... erm, sorry excuse me, 2 GB, is good enough for anyone-
For small business that didn't have the luxury & money to buy a server and licenses required to support such, I would have recommended MySQL or PostgreSQL as a data store with Access as a front-end client. In fact that's how it was done for the last nonprofit company I worked for, though it wasn't for the want of size but rather for want of transactions*, logging*, and remote access without spending a penny and making do with old hardware.
* To be clear, both can be done inside a pure Access solution but require additional implementation and codes to support such functionality; but I say why re-invent the wheel?
Anyway, so to me, Access's 2GB size limit is quite reasonable when we're looking at it as a desktop solution. But as soon as a business take it up and make it their critical mission application, they will have to be prepared to support it which may include taking it beyond its capabilities by enabling a backend capable of addressing more than 2 GB.