If a business deal that will make or break your startup depends on whether you can deliver or not, would you rather go for the money and put something in place that's horrible by everyone's standards or implement it correctly, lose the deal and have more such pressure? Doing things 100℅ correct is a luxury not everyone can afford, especially early stage startups, I've seen some horrific code in my life but that horrific code closed the deal, made the owners millionaires and after that they spent plenty of time catching up with the technical debt now that they had the luxury of doing things properly.