Renesas/then-Hitachi H8 and Microchip PIC were popular in Japanese EE colleges and Universities. The H8 was always a bit too advanced, more popular in more niche robotics than plain EE, and must have been not too important for Renesas. But the latter was blown away entirely by AVR as Arduino came around and created a whole hobbyist industry.

IDE and API won't be issues, it's just bare C/C++ and APIs are just extra standard libraries. But the popularity of Arduino and ATmega328P/ATmega32U, its expanded talent pools, etc must be somewhat tempting and potentially-vital-looking for Renesas, while also not too tempting nor threatening to make substantial changes to its operations and focus on over the counter chip sales.