If energy prices reflect externalities, you wouldn't need any special regulations or official ratings to give people incentives to get improved appliances.
Energy costs are already giving people incentives to do so, but perhaps they aren't high enough?
There is no way to know how much the oven is using. Even noce purchased, most people have no idea how much energy in their home is used by what (they just get a single bill and for an entire 2 months period).
Lastly as noted, at least here, the majority are installed by builders and included in a package price - the consumer doesn't choose and most builders don't offer an option. Many more would also be chosen by landlords for those who rent, rather than home owners. Or may have been chosen by the home owner that built the house you then purchased.
Thus I would say the number of consumers that directly choose and purchase the oven they use would be a low percentage, and the cost to replace it is high enough to make that unlikely and not have a great payback period.
Eg in Germany people routinely check out how good the insulation on eg the windows is when they choose a place to buy or rent. That's because energy is expensive in Germany, and it gets cold enough in winter that you need to heat.
If energy is cheap enough, people can be rationally (!) ignorant about these issues.