They have claimed multiple times that before the App Store you had to get your programs from a brick and mortar store at a large commission, which justifies their 30%. Conveniently omitting that internet has already existed.
https://www.politico.com/news/2020/07/28/tech-ceo-antitrust-...
> Opening statement from Apple CEO Tim Cook
> When the App Store was created, the prevailing distribution options available to software developers at the time did not work well. Brick-and-mortar stores charged high fees and had limited reach. Physical media like CDs had to be shipped and were hard to update.
> From the beginning, the App Store was a revolutionary alternative.
> App Store developers set prices for their apps and never pay for “shelf space.”
[...]
> [Apple’s commissions] are vastly lower than the 50 to 70 percent that software developers paid to distribute their work before we launched the App Store.
"Did not work well" is 100% true. It is not the same as "impossible".
I've never heard them claim that. The claim is that for an appliance like a phone - rather than a general purpose computer - device reliability trumps all, including the ability for the consumer to run arbitrary code on the device.