Your key points there are 5w & 7.5w.
What I meant was that if iPhone 12 owners want wireless charging at decent speeds (15w or above), then they'll need to buy the Apple 20w brick together with the MagSafe charger (or another supported charger by one of the other few select brands).
For the time being, that is the proven solution.
However, recall that at one time, Apple's 2.1A, then 2.4A adapters were the fastest form of wired USB charging on the market, but initially only supported by Apple's own, and select 3rd party adapters.
At the time, the USB governing group did not see the potential in USB as a power delivery solution, and the power standards in the USB spec were rather limited, since it was envisioned as a data conduit, not a power conduit.
Before its portable devices moved to USB, the OG iPod and 2G had a FireWire interface that handed both data and charging. FW, being a robust, heavy-duty spec (that deserved a better fate) was capable of supplying a max of 45W, at 30V, with variability. The relatively small battery didn't call for that kind of power, so the supplied adapter was sized at 12W (1A), which was more than adequate to provide a good UX (80% charge in 1 hr, 3 hrs full).
The iPod later transitioned entirely to USB with the 4G, and was given 5W adapters, which doesn't sound like much today, but was adequate and pretty much the norm at the time, as well as resting within the confines of the USB spec.
Those needs changed when the iPad, with its large battery, appeared. The prospect of charging a ~25+ Wh battery at 5W (do the math) was not an enticing proposition or good UX, then, or now, so Apple needed a solution with higher power capacity.
So, Apple being Apple, it came up with its own twist, a 10W, then a 12W adapter with its own coding, to meet its needs.
There was little, if any, 3rd party support for Apple 2.1/2.4 in the beginning, but eventually, that changed as the market adapted, and it became ubiquitous, despite, to my knowledge, never being made an official part of the USB spec.
Apple's history has shown that it has shown no hesitance to make deviations from standards when it believes it will benefit its users. Apparently, few can answer MagSafe's specific equest for 2.22A at the moment, but that will change, and more options will appear, just as they have for 30-pin cables, Lightning cables, and so on. This is just the beginning for the MagSafe ecosystem, and users will probably be fine.
It should be noted that Apple is not alone in deviating from industry standards, when it comes to faster charging solutions.
Those who don't want to risk cuts or receive surprises should stay away from the bleeding edge. Apple's knives can be pretty sharp.
