mraig,
You are not wrong about that. A lot of people that are not making it in graduate school (whether it's academic, personal or financial) feel very frustrated and bitter when they finally give it up. Usually at this point they are also really, really broke. I've known a few people in this position too, and I was surprised to hear them talk fondly of grad school a year later, once they found a job and were on their feet, away from the stress and frustration of arguing with an advisor they just couldn't communicate with and having to pay for an extra semester of fees because their thesis was not acceptable, etc. etc.
I think no one can know how they're going to do. Just cross your fingers and hope things work out for the best.