@y_sasaki, you raise an interesting point. Yes, perhaps, what the core achitecture won't matter that much.
If so, I am wondering that some system vendors prefer a particular SoC because that particular SoC vendor might offer a lot of support (and handholding). Then, the decision on an SoC rests on the amount of [free] support OEMs can get...
When we pick a SoC for a product, we pay more attention to peripheral support, low power mode support, supply chain stability and price, rather than core architecture difference. As long as good devtool (compiler/debugger) and middleware (RTOS / device drivers / protocol stacks) are supported, core architecture difference do not mean much.
And as you know, ARM/Cortex chip manufactures / middleware providers / devtool providers have established great ecosystem for embedded applications. I think it is a major challenge for chiniese MIPS manufactures if they can provide such support foundation, rather than just to provide (even cheap, highly integrated, high-performance) silicon.
Its MIPS-based processing core's low-power profile aside, Imagination's MIPS technology "will need to get adopted by a major chip supplier in order to have the best chance of breaking in," says Francis Sideco, senior director of Consumer, Mobile, and IT Electronics at IHS.
I would certainly consider Microchip (which uses MIPS cores in multiple product lines) to be a "major chip supplier" !