The issue I see here, is that trying to assert "can survive outside the womb" as the meter stick can run into some nasty consequences later down the line.
Take for instance, if reproductive medicine is able to create genuine artificial wombs-- say, for same-sex couples, such as homosexual males. Since this hypothetical technology is able to sustain a fetus from conception to full term, without ever even being inside a (human) womb, the pro-life crowd instantly wins. Women need not be involved in the process at all if they wish, and the fetus can still survive.
This is where the argument about "convenience" comes in-- forcing somebody to either cary or pay for the continued gestation of another human, that they really cannot afford. The pro choice crowd would say that it is inherently immoral to force somebody into that position. The pro life crowd would say it is inherently immoral to terminate a perfectly good human life over money concerns.
Sensible policy makers should cut the bullshit-- literally-- and focus on how even in such a far off future context, the issue can be resolvable. In this case, streamlining fetal adoption so that legal custody and authority can be quickly and readily transferred, for the benefit of the child.
Like it or not, with organ printing technology on the horizon, the prospect of a functional synthetic womb is becoming less and les science fiction. It isn't wrong to consider it in policy decisions.