The thing about tech problems is that they don't show up as tech problems unless they are really bad. They usually show up in lack of product-market fit, lack of adoption, high turnover, and difficulty with sales and marketing.
For example if you chose Electron for your app and put no effort whatsoever into slimming down what you are running inside, users might decide they don't want to use your app because it uses too much CPU and RAM. If you use a slow database as your SaaS app/site's backend, your site will be slow and users might bounce during trial. If you pick an unwieldy, bug-prone, or weird (a.k.a. hard to hire) technology you might experience a slow development cycle and find it hard to build enough features or fix enough problems.
Most of the time people won't tell you these things. They'll just move on. Some of them are subconscious, like performance issues. The app just doesn't "feel" good, it's not a pleasure to use, etc.
If you are trying to sell shit on a stick, your problem may not be marketing... but you can always blame it on marketing! If your stack makes your development cycle slow, maybe you're not finding product-market fit because you're hiking through the woods with an elephant strapped to your back.
Good tech choices are fundament. They enable everything else to work well. You need everything else of course... good tech alone won't cut it. But the rest of your company's operations are going to flounder if they are not properly equipped or if the product sucks.