Arguments like “but it works” or “it gets the job done” are tell-tale signs of someone happy at the lowest level of the technical hierarchy and your cue to just quietly back out of the debate. —DHH 
I bet you over-engineered your startup:
Of the three startups I've worked with, two of the three were ridiculously over-engineered monstrosities that were way over time budget. It was clear that the CIO/CTO wanted to do cool fun stuff and not build a marketable product.

The other was cobbled together with completely shit code, was constantly breaking on releases, and was glued together with perl scripts. They're now publicly traded.