Yes, Apple could do many things. But have you ever looked at the regulatory nightmare of just running a business these days? Governments have involved themselves in basic software and hardware decisions.
They aren't just going to sit back while Apple facilitates payments in something that triggers a taxable event in most countries when sold. It would be tax and regulatory hell on a level they probably haven't had to deal with yet.
The users would have to deal with the tax implications too.
A lot of innovation will be stifled by tax law until those laws are removed.
It's subtle, but I think the issue is that most people put far too much focus on companies (usually in the form of blame) rather than governments that control almost every economic decision everyone makes.
Apple could do this, but only if governments are removed from economics. I don't see that happening any time soon.
