Dontshrink what does your wife think about caring for you on a vent?
You do need 24/7 care, if the vent stops working even briefly, well so do you.
Your wife may be willing to increase her level of care, but she will have to sleep, and so you will need many family and friends to fill in the gaps and be willing to take care of someone on a vent, or you will need to hire home help to fill the gaps.
Debbie and Jane truly tell the vent story from both sides.
You haven't said here what kind of level of progression you are at now?
The way I figure it is, if your body is failing and the breathing is going last, then a vent is going to keep you alive but bedridden, possibly locked in. If your breathing is failing well before your body, then you may gain some good quality time by venting. Please be aware however that this is only my opinion, it's a very personal decision!
So many things to weigh up, and I would suggest that considering your wife as primary caregiver is the first important item, then finances.