Too much complexity without any benefit (when adjusted for new failure cases and cost of additional components and complexity).

Electronics is mostly KISS, not only motivated by the financial factor but also reliability, manufacturing, etc.

So far micro controllers are too expensive, too sensitive to unstable power supply, too complex in general (requiring some support components in some cases, have an additional prefabrication step for flashing firmware by the chip vendor, and cost a lot more.

There is no clear advantage to the approach you mentioned.