That’s unfortunate on one side, but not completely without ground on the other. We jumped ahead as an industry quite a bit and there’s a lot of knowledge out there to use.
Of course doing research can lead to better results, but in many cases the “upgrade” wouldn’t be worth the research time and cost.
If the product you’re building doesn’t compete on the actual “app” or “website” side, but instead competes with pricing or some “behind the scenes” elements, you can safely use some heuristics and base it on other successful app designs.
In an ideal world all products would be planned and thought out / researched but this world’s far from perfect :)
We just have to fight our battles and do the best work we can in things we CAN control.