Well, that depends on why the failure.. if it's because of lack of funds or knowhow, then it was doomed to fail from the start. I always try not to plan with what I call "virtual" funds for a project, meaning I don't have the budget to do it until the money is in my hands. I didn't even commit myself to a swap until I knew the money for the motorset was there.
Even then, buying an engine, yanking out your own, and things ending there, with the other engine collecting dust in the side of the garage, that's not failure from trying, that's just FAIL.
So yeah, it depends. If it CAN be done, I say DO IT, but if you're not really in a position to do so, save your duckets and do what you CAN do. That's all I'm really suggesting here.
And I'm not opposed to these threads, so long as we understand that it's just TALK until someone shells out the cash and blood/sweat/tears and makes it happen.
Right now, this is all internet engine swapping, not reality. Can it be reality? That's TBD.