Most HVAC appliances are now very efficient, and water heaters remain the last bastion of opportunity for energy improvement.
We are seeing high efficiency water tanks and even heat pump water heaters enter the market. I have one in my home. The big challenge in this area is rental programs: owners of big water heater rental portfolios have a vested interest in maintaining the status quo in your home. Upgrading to more energy efficient units isn’t going to happen in this environment - you need to own your own tank so you can control the cost of operating that appliance in your home and to ensure the most advanced product.