Just charge everyone the top cost and give them all the fastest chip?
This sounds like a good option, or at least an option worth considering. I don't think the cost would be "top" though. It would be somewhere in the middle. I think the cheapest bargains would vanish, but so would the most excessive markups for the cutting edge.
There are two ways to look at the situation. One way to look at it is to say that bargain hunters will not buy a CPU unless it costs $200 dollars or whatever the bargain price point is at these days.
Another way to look at it is like this. Cutting edge performance enthusiasts are more than willing to pay absurd amounts of money just to be able to feel that they are at the very top of the performance heap, and to be able to brag about it online for a month or so. If that's the case, why not create a product structure to milk that money out of them, if they are so willing to part with it?
Either way we know that the CPU business is highly profitable with the tiered price structure that it uses. In other words, the bottom dollar CPUs still generate profit, or they wouldn't be sold just to please the bargain hunters, would they? So if we start charging people a fair price for what the CPU really is, without artificially crippling the CPU, I think the price would normalize somewhere in the middle instead of at the top.
Whatever big businesses are doing it's almost always for their own selfish benefit and not for the benefit of the consumer. Businesses are not charities after all. So if a business creates a tiered price structure, it does so not so that it can serve the consumer better, but to extract more money from the market.