Any advantage in AC-DC or DC-DC with past, large form factor semiconductors?
The main advantage of using IGBTs and MOSFETs over thyristors is not their smaller size (I honestly don't know if they even are smaller for the same power-handling capacity) but their higher efficiency and greater controllability. Thyristors have always had a flaw that they are very difficult to turn off; it requires waiting for the next mains zero crossing or, in the case of a GTO thyristor, shunting very large amounts of current out the thyristor's gate through your control circuitry.
IGBTs and MOSFETs don't have this problem; either type of device can be turned off by simply driving the base with the same type of control circuitry used to turn them on. MOSFETs in particular are also much more efficient than thyristors, since they act almost as resistors when turned on, rather than having a relatively large (though relatively fixed) voltage drop. (IGBTs still have their saturation voltage, though. I don't remember off-hand how this compares to the voltage drop of a thyristor.)
On the other hand, sometimes you do need higher voltage withstanding and current capacity than you can reasonably get with solid-state components. Until relatively recently--into the 70s and 80s, I believe--mercury arc rectifiers, a type of electron tube, were still used in some high-power applications such as radio transmitters. The development of higher-quality solid-state devices stopped that, though, as silicon diodes and thyristors are much cheaper, and don't contain environmentally-hazardous mercury metal.
It's not a power electronic converter, but there are still vacuum tubes in common use today as well. The magnetron in your microwave oven is in fact a vacuum tube, because there is currently no economical way to generate that amount of RF power at the appropriate frequencies with solid-state devices. That may change in the future, but for now, you still have at least one vacuum-tube-based device in your house--as long as you're one of the large proportion of people who have a microwave oven, anyway.
Klystrons and travelling-wave tubes, other types of vacuum tube that are actually fairly similar to the magnetron, are still in common use as well for amplifying RF signals, especially in radio and TV station transmitters, as well as on communications satellites and in particle accelerators, where unusual requirements lead to them being the best choice in some cases.