Years ago most drive mfrs went to using a set of power devices integrated into a single unit, called an IPM, Integrated Power Module. Up to about 10HP, they are about the size of a credit card, or better a stack 0f 10 credit cards (thickness). Inside that single unit are the 6 diodes for the bridge rectifier, the 6 transistors and the pulse firing control for the transistors, plus some smaller ones also throw in the DB Chopper and control. You cannot open it up and replace any individual device, there essentially are no individual devices any longer. It's all one monolithic silicon structure. When it goes, it's gone.
The rest of the VFD is just a PCB with the logic, which is giving firing instructions directly from the mP or DSP, the caps, the HMI, Comms and I/O, usually on one board. The board connections to the IPM are surface mount, no wires or cables with connectors to un-do for servicing. So the time it takes to even investigate a problem exceeds the value of the drive. IMPs are used in larger drives too by the way, but they are connected with cables so they are easier to replace. But you still have the issue of not being able to replace only one specific failed device, you have to replace the whole shebang.
Older small drives that used discrete IGBTs and separate diode bridges are technically repairable, but with the advent of cheaper smaller IPMs, discrete IGBTs are harder and harder to find, translate: expensive. Then you have to deal with the relatively finite life of the capacitors, so even if you go to the time and expense to repair a power component on a small drive, it's probably getting long in the tooth if it still had IGBTs, so it isn't going to last much longer anyway.
Kind of like being hit with a $2,000 vet bill on a 16 year old dog...
