For having worked in the automotive industry this is very unlikely to be a result of *cheaping out*, every car components are a compromise of pros and cons that the engineers try to get the best balances and prioritize. Maybe Mazdas trusted supplier of these parts doesn*t have that system available, do you risk changing suppliers for that features, with all the unknowns in integration and reliability that comes with it ? Maybe the human factor engineering team decided that having an extra menu in the dash to be cycled through wasn*t worth it ? Who knows
Based on the feedback from this post, some people really would have liked that feature. I personally don*t care at all for the tpms sensors and finds them more of a nuisance in the cars I have owned (and usually don*t fork the extra 60$ per rim to buy some for my winter rims).
All to illustrate the point that a lot of these features requirement and integration for a vehicle of that price range are very subjective and more complex than people think. i had a friend with a BMW M3 that couldn*t play music over Bluetooth while my 2 year older mazda 3 could, these are not cost saving decisions.