Bipolar transistors for power electronics is much less efficient than MOSFETs, its not used any more (thyristors apart), the trend is to SiC and GaN MOSFETs and away from silicon even.
MOSFET efficiencies can be > 99%, MOSFET switching speeds are 100kHz and up these days, a bipolar
switching device would be pushing it at 20kHz due to the sluggish turn-off behaviour. Higher switching
speed = smaller inductors and capacitors, less board area and less cost.
For high voltage power conversion IGBT's take over from MOSFETs, they are a kind of MOSFET/BJT
hybrid better suited to high voltage (more rugged to voltage transients). SiC MOSFETs are likely to
take over from IGBTs to some extent from what I read.
The body diode an issue? its actually a boon for power conversion and is sometimes bolstered with
parallel schottky diodes to improve performance. IGBT circuits have to have diodes added specifically
because an IGBT doesn't have a body diode.
Its only linear amplification where BJTs stand out as a good fit (although secondary breakdown is
a big achillies heel for high power amplifiers).