The engine end of Tecumseh was in deep trouble and the quality of the casting and parts shows how poor the condition of the tooling many of these things were made on was in before they went bust.
There comes a point when something is so cheaply made that aftermarket parts are better.
Where did you get that information from? From the ten or more Chinese carbs I've purchased as compared to the six or seven Tec carbs I've rebuilt, the difference in casting is night and day. Even the new replacement Tecumseh products labeled as "Tecumseh" not Oregon and the like, are vastly superior to that $15 piece being discussed here.
You blame Tecumseh's diminishing casting skills not rendering and easy copy job for the Chinese copier???? Please don't apply axioms to an article unaffected by broad-brush internet lore.
1971 MB1A, I have received three of those $15 carburetors that were so poorly cast they wouldn't retain the hinge pin for the float. I returned them of course. On virtually all of them, the bottom (high speed) jet housing is torqued into the bottom so tight that the gasket is distorted and ripped, requiring replacement. It takes two hands, that's how tight those Chinese kids torque them.
You take your chances for $15. For me, if it's a bike I plan on riding often, or one I've spend a lot of money restoring, I opt for an actual Tec carb, which is about $80. While tuning and riding, you see the difference. Is that difference worth $60 more? In some cases not. But I'd never compare them to each other. They're band aids. If you get these carbs, retain your original parts, like needle valves and jet housings. You might need them.