Having the powertrain always connected to the wheel allows instant power delivery. The power delivery response is instant (especially after slowing down). It is the same feeling of driving an EV. Once you get used to it, you can’t go back to anything with a torque converter.

If you are talking about transmission in the sense of multiplying torque to change the trust at the wheel, Prius does not have one. Two propulsion systems deemed it unnecessary.

In Nissan’s hybrid case, it requires another gearbox to multiply torque. Hyundai’s Blue Drive, Honda’s IMA, GM’s two mode, Porsche’s hybrid, etc… all need a separate gearbox between engine(s) and the wheels.

The only other hybrid that is a single speed but also acts like a CVT is Chevy Volt (series hybrid). Tesla EVs and Nissan Leaf is also single speed CVT.

The other effect of this simplicity (the lack of any clutches) is that there is no “Neutral” gear, only the promise that engine/motor speeds will be matched to act like it’s in neutral.

Why should that be any different for the development of alternative fuel cars? Car companies are not a charity that works for the common good – they have to make money, they have to recover investments. Yes, it would be nice if they would throw it out at cheap prices – but they can’t, or they would go under. If they don’t get government support for developing those things, they have to charge the luxury fee in the first few years before they can give it out for cheap.

Like it or not – but that is how every (tech) business works.

Nissan hybrid is more complex than Honda’s IMA because it has two extra clutches and the electric motor is bigger. The e-motor is IMA acts as a flywheel, starter, alternator and boost the torque. The e-motor for Nissan hybrid do more than that and also take over the function of the torque converter.

Nissan hybrid requires a gear box (automatic or CVT). That alone makes it more complicated than Power Split hybrid (mechanically). There will be more maintenance and point of failure to worry about. Mechanical gearbox also mean there will be restrictive operating area that would prevent the most efficient range (lowest BSFC) from the combustion engine.

Power Split hybrid (Ford and Toyota) does everything Nissan hybrid can. On top of that, the e-motor in the Power Split hybrid takes over the job of the mechanical transmission. e-motor is actually used to multiply torque to the wheel using electricity (instead of changing gears). This is why it is called eCVT (electric transmission) like an EV with a single gear ratio. There is no reverse gear because the e-motor simply spins backward (combustion engine can’t).