Do you think Apple's store for MacOS failed for the same reasons?
This and the fact that the application itself is quite terrible.
Edit: Also, for desktop apps the pricing model without paid upgrades is not viable. Compared to mobile, there are too few customers.
The biggest hurdle in the macOS App Store is the stiff sandboxing rules that make the more exotic and often useful utilities incompatible.
Nope. The really big hurdle is the 30% cut that Apple wants to take.
For smaller devs the store should provide a better marketing and sales platform, and so be worth the 30% cut. Steam, as an example, seems to work out alright for most companies but not everyone.