The fact that Apple charges ANYTHING for the developer program is offensive on its own. It's not "normal". Microsoft doesn't charge you anything to develop for Windows, No Linux vendor charges you for developing and packaging software for their distribution.The yearly developer fee pays for access to Apple’s development resources, including code development support, downloads, beta programs, and education. It does not constitute a license to make money from the use of their libraries nor customer acquisition fees. This is clear because Apple has always charged additional amounts for for-profit apps. Pretending the $99/year fee covers all the benefits of being licensed to operate for profit in the Apple ecosystem is naïve to the point of being maliciousness.
Generally you entice others and yes, sometimes even PAY others to come develop for your platform because it makes your platform more enticing.
Apple is the odd one out, wanting to both have their cake AND eat it too, not the other way around.