The RA4M1 is an ARM Cortex core, but it could be that Renesas offered to subsidize some of the cost of the board by providing the chips with some kind of sweetheart deal. Not a bad idea if so, Renesas can generate a whole lot of interest in their platform for what is probably a rounding error in their bottom line. And they've previously invested in Arduino (https://www.eenewseurope.com/en/renesas-backs-arduino-with-1...).