Nobody wants to spend their time micromanaging their electricity usage to such a point. Such a scheme to all users will never pass. Lack of day-ahead means it's impossible to plan anything.
You can still plan based on day-ahead prices. And just take the risk on the difference between day ahead and spot pricing if you like. And if you don't want to take that risk, you can buy contracts for difference between the two from someone else willing to take on the risk. And if you don't want the hassle, you can sign up with an electricity provider willing to do all of the above and not even tell you about the complexity of such stuff.