Just found that TI is going into M0+ world. Don't understand why? Now?
Sure, why not, to expand their offering?
It's a trend too, several vendors are currently expanding their lines with lower-end MCUs. Which makes sense. They don't want to loose too much ground to chinese vendors, which many have turned to, not just for cost reasons, but due to the shortage. Now that the shortage has eased, the damage is done and they absolutely need to do something to regain traction.
ST is also focusing on having a low-cost 32-bitters offering with the STM32C0, also M0+ based.
And what happen with MSP432?
I don't know if they plan on retiring it or not, do you have info about that? But I'm not sure why you'd compare those with the new series.
The MSP432 is a Cortex M4 and was their first low-power MCU (AFAIK) after the MSP430 which was a 16-bit proprietary architecture.
Maybe you meant 'what will happen with the MSP430' instead?
The MSP432 itself was never a great commercial success as far as I've seen, so whether the new M0+ series will crush it or not doesn't really matter. But, topping at 48MHz max IIRC, even a M0+ at 80MHz may get you more performance, except if you need a FPU.