"This is almost good, here's a thought, let me select my provider, enter my account number and account password and "it just works", really what is the point of a SIM card at all?"
Because those providers require SIM cards to attached device ID's to your account number. Without them, simple cellular devices wouldn't be able to work. But again, this is a question for the cellular providers, not Apple.
"Here's another thought, 99% of of (smart)phone hardware is compatible, why cant I dual/triple boot or even select the OS of choice at first boot up?"
The reason you can't is because you're wrong about 99% of hardware being compatible. The other reason is because hardware manufacturers want you to purchase software from their ecosystem, not the competitors. This is the reason why iOS (an apple software product) is only available with iPhones/iPads (apple hardware products). It's the same reason Samsung won't let you boot into iOS.
This is simple business. It's like going to Taco Bell and wanting to purchase a Big Mac.
This article lacks the basic information about this SIM card, is it CDMA or GSM. Having there Sprint (CDMA) and AT&T (GSM) thrown together it does create confusion, especially if you keep on mind that those two standards do not mix together and how CDMA works.