In order to be efficient and powerful, a steam engine needs high-pressure steam, which can only be safely contained by thick, heavy boilers and pipes. This makes miniaturization of steam engines for cars difficult. Gasification of wood allows you to keep the benefits of the internal combustion engine.

I think the bigger issue is adapt vs rebuild.

The Doble steam cars are at least on the cusp of practical.

(they are very high maintenance compared to modern cars)

Thanks; I had never heard of the Doble Steam cars until now. I found this video of Jay Leno driving one.

https://www.youtube.com/watch?v=rUg_ukBwsyo

An ICE car of the same era is also high maintenance as are say cars from the 60's

Modern boilers are coils of thin copper tube that heat up quite fast.

You can run a gasifier out of almost any biomass, coffee grounds, wood, leaves, corn husks. Then with minor modification you can run most cars on the resulting syngas.

I knew an elderly chemist/inventor who told of how he once converted his wife's car to run on cocoa bean husks. He said you wouldn't know the difference except for the slight smell of chocolate as you drove around town.

I want one of those "Mr Fusion" devices from Back to the Future for my car (and my house too, now I think about it).

I wonder if you could power a turbine with wood.

Yes, you can. A few people have built wood powered jet stoves, using car turbos:

https://youtu.be/E-8BX7dUk5c

No power takeoff from the turbine in this case, of course, but the principle is sound.

Oh wow. I had been thinking about such a device for a couple of years now, great to see one in action.

The main problem is refueling, because the combustion chamber has a higher pressure. With a liquid fuel, you just spray it in at pressure, but with wood that isn't possible.

... refueling: I'm rather certain that there are wood pellet stoves and furnaces with automatic feeding.