You buy hardware for what it can do now, not for what it may bring in the future. You will be always disappointed if you think you are going to get any new features than it comes with. You did not sign any agreement with Apple to provide you with new features.
People who buy Intel Macs right now should not be looking at what macOS Monterey is going to give them, they should be looking at what Big Sur on that specific Intel Mac is giving them out of the box. Do not expect anything more, be surprised when they do give you new features but you should never expect it or expect Apple to be obligated at all to give you new toys.
Yes, it will. They did it before with Intel transition. The only reason this feels quicker than Intel is because of annual releases as opposed to 2-3 year release cycle we had back then.