Why won't car manufacturers offer AWD on their economy cars like Subaru does?

Cause fuel economy. An AWD Suzuki aerio or SX4 or Kizashi is quite a bit worse on gas than the FWD versions.

"HEY LETS WASTE GAS ON OUR GAS SAVERS SO WE'RE COOL TO YOUNG BUYERS"

It's a luxury. You do not need AWD except for off road and extreme snow. That's why the feature is found only on Acuras and Lexus, not the cheap cars. X-Drive and 4Matic are also very nice, again you pay $$$$ for something you simply do not need. No different than heated seats or a big touchscreen infotainment.

Because AWD kills fuel consumption which is the entire purpose of an economy car.

Jag does

Good work telling people what they need and don't need

From what I can research, the Axela is using the "i-Activ AWD" system found on CX-3/5/9 models.

It's an on-demand "intelligent FWD-slip-and-switch-to-AWD" system, like in the CR-V and most other crossovers.

Mazda i-Active AWD presentation:
youtube.com/watch?v=rPyRCkt1GHw