I think terms like "entry level" and "upgrade" is nothing more than "BS" and a marketing ploy as an attempt to work on human gullibility and greed. By naming something "entry level" or calling an item "an upgrade" it makes the owner feel like they need to "keep up with the Jonse's" or the "neighbor next door." It's hog wash terminology in my opinion and an attempt to create a guilt complex. And... lots of folks fall for it, so end up buying the "upscale" model that is still as cheaply made as the low-end scale identical item.
To answer your question, I do think manufacturers are using inferior products. I don't think they are doing it deliberately though. I think we are all Guinea pigs in a laboratory petri dish though. Manufacturers are constantly experimenting with cost reduction and improved materials. Sometimes, BOTH fail. Having watched the RV industry rather closely now for some time, I'm of the opinion the newer models are all experimental again, revamping old proven methods for a more modern, cost saving, eco-friendly, light-weight, cost-saving product .... that just REALLY does not hold up over time! So the experiment continues and we... the buyer are the Guinea pigs!