There were no guarantees with any of the stores. Many didn't even host stuff they sold. So you'd buy from the "App Store", download from the developer's site, and then deal with whatever license system the developer used. Since there was no standard way to work with the store there was no standard mechanism of distributing licenses. Signing was also a joke as there was no good way to let end users validate, in a usable way, the signatures of apps or even that the signing entity was who they claimed to be.
Piracy was rampant because stores sucked, prices were onerous, and cracking the software or just sharing licenses was too easy. The current App Store model developed as a response to a broken market for mobile apps.
Hate on the App Store model all you want but it solved significant problems that plagued the industry for years.
Microsoft, Amazon, Google, and Apple already have my CC number. If I could buy all my apps through (ex:) the Microsoft store that exists on PC, Android, and iOS I could delete my CC info from Google and Apple. That's a win in my book.
Maybe the competition would force all of them to innovate a bit. Wouldn't it be nice if you could give your CC number, but set a hard limit on in-app purchases? Ex: Here's my CC, but you're not allowed to charge more than $50 / month to it. I bet there are a lot of people that have gotten multi thousand dollar IAP bills that wouldn't mind a better system for some of that stuff.
First of all, that is not true at all.
And second, even if it were true, it'd be a far better situation for developers than the current status quo.