"Arduino" is a brand of development boards. The direct equivalent would be the Atmel* ATmega168, and that was widely available through distributors, less expensive, had extensive manufacturer and community support, and was part of a broad product line.

What makes microcontrollers commercially successful is... commercial use. Hobbyist applications are fun, but they don't pay the bills.

*: Microchip hadn't bought them yet

The context here is decidedly hobbyist/educational.