It's not a very feasible lifestyle that's for sure. Also, living 24/7 as a baby wouldn't be fun for me, while I love my baby-side dearly and I enjoy my evenings or a nice full weekend padded up and regressed, I have adult interests too and I'm pretty sure my Mommy/GF would fancy a few breaks from caring and changing every now and then as well
Oddly enough though, I have heard of some ABs who have been able to manage this.
As HappyNotHappy pointed out, some of the cases I have heard involved Daddies who were self-sufficient and wealthy enough to sustain the lifestyle for their AB without needing a second income. In other cases though, I have known of ABs who work from home and do the baby thing 24/7-ish... I mean, they still work their shifts and such from a computer, but they do so while padded and onesied up.