Both AVR and PIC serve the education and hobby markets. The hobby market is dominated by AVR
This is a relatively recent phenomena. Pre-Arduino, the hobby market was dominated by PICs (and obsolete PICs at that), and the "easy" hobbyist market targeted by Arduino was probably dominated by "The BASIC Stamp" from Parallax. A bit before that (and occasionally since Arduino), Atmel AVRs were difficult to obtain from hobbyist-friendly dealers, and many of the semi-pro dealers (digikey/etc) didn't carry them. Usually programmed in Assembly Language; I remember ordering some ATmega48s as my AVRs with "lots of flash space" - the usual candidates with A90S2313 with 2k... (although - I notice that my perception of "relatively recent" is stretching out as I get older. Have I really been doing Arduino Stuff for a decade, now? Ouch!)
while education splits them about evenly: microprocessor courses taught in computer science or business departments most often use PIC.
(microprocessor courses in
business departments
!!!)
Microprocessor courses are relatively rare in general. :-( I'm not sure you can derive meaningful statistics.
All the growth seems to be 'vertically', away from 8 bit processors.
Indeed. PIC32 has more Arduino stuff than AVR32, but ARM is winning out.
Some part of me is half-expecting PIC and AVR to both die out as "odd proprietary architectures", leaving behind a bunch of 8051 derivatives for the 8bit crowd, and everyone else moved to ARM/etc. (8051 and ARM both being architectures supported by "many" vendors.)