Because media and game console publishers don't want you to be able to run games they haven't distributed (because they force game developers to work with game publishers, and game publishers to agree to all sorts of terms), or programs that can access media and games in a way they don't want you to.
If you think Apple is bad, wait until you see Sony's terms for publishing a crossplatform game on Playstation (Xbox is a bit better.) The agreement they force publishers to sign has all sorts of stipulations, including rules that require payments when PSN users spend more on the PC version of a game than they do the Playstation version, and a prohibition on moving purchased cosmetics to accounts on other platforms.
Nintendo, Sony, Microsoft - all of them would be dead set against third party stores. So would all the media conglomerates (that Sony doesn't own.)
Many software developers would also be against it. If you sell an app on the iOS store, you're virtually guaranteed it won't be pirated. That guarantee goes away the second iOS devices can use third party stores and run any app.
That TPM chip in every x86 system? That isn't there for you, friend (although now it can be used to store FDE keys.) TPM was for storing the keys to decrypt media files.
People seem to keep forgetting that many of the security systems in MacOS and Windows aren't designed for your security, but the security of licensed content.
if you have to distribute via website or alternative app store, everybody can always have a known person to be responsible for piracy, in addition, it is just as easy to block as apps in apple's app store
sony is not yet a gatekeeper, might be in the future... apple does not have to sell in Europe, if it does, and big enough (no need to be monopoly) to be a gatekeeper, law and rules say they operate a critical infrastructure/platform in the EU economy and hence they cannot tax developers (a country has such powers)
the question is not whether Apple has to change but a question might be why? this is the field of monopolistic power and competition law... monopoly profit is not inherently bad, can help innovation but along the way we figured out it is probably best to curb this power in the long run
Apple had its time of their life and to be honest, I see little meaningful innovation in the last 5+ years, however, they suppress competition and innovation in the economy, controlling a gateway between innovative developers and users
another aspect is consumer prices... should consumers get lower prices or let apple take monopolistic tax from them? of course lower prices seems to be better nd it is one goal... however, we should and we do allow success and monopolistic profit by each and every big innovation, in the beginning and Apple has already had that
it is a bit like an economy supports patent law and competition law at the same time
most people are motivated by financial success and most company pay research and innovation for potential monopolistic profit and this works and it is protected! however, competition law or new forms of it like DMA kicks in later on
it is like you innovate, use patents, get big money but if you grow big you are not allowed to become like all companies become if not controlled: shifting from competitive innovative power to a country like taxing power
I think it is correct that we need competition law too, if we really think about our past, economics, history, and what motivates people
If you think Apple is bad, wait until you see Sony's terms for publishing a crossplatform game on Playstation (Xbox is a bit better.) The agreement they force publishers to sign has all sorts of stipulations, including rules that require payments when PSN users spend more on the PC version of a game than they do the Playstation version, and a prohibition on moving purchased cosmetics to accounts on other platforms.
Nintendo, Sony, Microsoft - all of them would be dead set against third party stores. So would all the media conglomerates (that Sony doesn't own.)
Many software developers would also be against it. If you sell an app on the iOS store, you're virtually guaranteed it won't be pirated. That guarantee goes away the second iOS devices can use third party stores and run any app.
That TPM chip in every x86 system? That isn't there for you, friend (although now it can be used to store FDE keys.) TPM was for storing the keys to decrypt media files.
People seem to keep forgetting that many of the security systems in MacOS and Windows aren't designed for your security, but the security of licensed content.