20 years is a generation, however for many of us, Apple's walled garden was a refreshing concept versus the mobile operators gardens.
First of all, getting SDKs was akin to console devkits, back in 2004 getting a Symbian SDK was still a commercial only product for example, same for Windows CE/Pocket PC,...
Followed by about 80% tax, only to be listed on mobile phones magazines, with the SMS code to trigger the application download.
Hence why everyone rushed for the garden, it was indeed easier to be creative in Apple land.
Now 20 years later, there is another reality.