> Everywhere I've worked where I'm expected to be reachable by phone offered a stipend to pay for the service.

Well your experience is more the exception than the rule today given my friends, family, and own anecdata.

> An abusive employer is going to make unreasonable demands of you, regardless of whether you use your personal phone for work.

Let me know when there's enough employers that most people without negotiating leverage can actually be employed by one that's not abusive.