Whatever it is you're writing doesn't have to work for the next twenty years. If it's sufficiently simpler and cheaper, it's fine if that project only works for the next five years, and you have to start working on a rewrite in four. By then, you'll either have gone broke (in which case the extra scaling would've been useless anyhow), or you'll have four more years of experience to guide you in how to build the next generation.

In your particular case, that MS Access DB was almost certainly the right choice when it was written, and the gotcha in that story is that they didn't start planning the migration away from Access until it was too late — effectively, they didn't pay off the tech debt when they should have, and got foreclosed on.