I'd argue that it is till the case on Android.
Yes, alternate stores are possible, but they are severely handicapped. First, manual APK install has to be enabled in obscure settings that come with a "scary" warning. Then they can't provide auto-updates but require a manual confirmation for each version update.
Epic gave up on running their own store on Android due to the difficulties.
I do think that regulators need to force Apples hand - not being in control of your own device is not acceptable.
But even then most business would remain on the official stores. We also need legislation to curb the excessive fees charged by both Google and Apple.
A few years ago the EU limited credit card transaction fees to 0.3% or a fixed maximum, whichever is lower.
A similar cap is needed for app stores.