Tractors are made to work - they should run at standard revs 8 hours a day for 5 days a week quite happily. Poor maintenance or abuse is more likely to kill it than using it for what it's designed to do. If you took 3 hours to blow it, and had 10 decent snowfalls a year, that's still only 30 hours a year. You'd put more hours on it mowing the lawns (which also runs wide open throttle).
Having said that, a BX does feel a little small for that job - and a cab would be really nice. All comes down to budget, time and comfort. It'll do it, a
B2650 will do it faster and in the warm.