This isn't new. In WW2 there was a lot of investment into putting hybrid propulsion into military vehicles. The US had the T23 tank, the Germans had the VK 45.01 (P) tank, and the Soviets had the IS-6 tank. It turned out that hybrid propulsion was both too expensive and unreliable. You needed a lot of copper to make the electric system and that was a scarce material in wartime. The electric systems also had issues with overheating and lack of waterproofing.
Hybrid propulsion was used even earlier in turbo-electric systems for battleships such as the USS New Mexico (1915) and had substantial advantages: redundancy and increased watertightness, better internal arrangements allow more optimal hullforms, the ability to start/stop/reverse on a dime to perform complex maneuvers and dodge torpedoes, motors running at their optimal speeds at all times leading to 20% better fuel economy, etc. Yet despite those benefits, when the Great Depression and WNT hit the next ships switched back to simple geared turbines. There wasn't enough money or tonnage for it. Nowadays we are talking about IEP which is just the same idea all over again.
Or that the first car was an EV, later superseded by ICEs due to the EV's technological immaturity.
Electricity technology is just starting to get to the point where past ideas are actually feasible; that's all.