Now that most vendors offer a diverse variety of ARM Cortex-M chips, why would one pick a Renesas or Freescale product? I understand that there are reasons for somebody to go with a PIC32 as they are familiar with tools etc, there also reasons to use a 16 or 8 bit MCU from TI or Atmel as they might think it's somewhat more suitable for their design, but why would one want to use a Renesas RX or Freescale ColdFire?
I think the best answer to this question, which gets asked a lot, is to look at a good survey. Embedded has a very good survey and it includes many factors.
Look at it and you can see many of the factors motivating people:
Some of the factors you mentioned, and many others are covered and reveal a wide variety of factors play into the selection. Familiarity with the parts dominate, but the strength of the ecosystem is very important.