The B-1B is a heavy fighter plane in agility and a heavy bomber in payload. The B-1(A) was NOT originally designed to fly in with heavy jamming; the onboard jammers were added in the B-1B program after the fact.
It was designed to fly faster than any fighter down as low as 50 feet off the ground. (Typical training takes place between 600 and 1,000 feet altitude in fairly flat terrain, way higher than the plane was designed to fly.) You have to realize that radar-homing missiles have a tough time picking off targets along the ground, especially from behind. If you want to improve the chances of interception with a radar-homing missile then it needs to approach from headon. Problem is the ultra-low approach to target allows the B-1B to hide along the curvature of the earth long enough to get under most air defenses.
Infrared homing missiles have a fairly tough time picking the B-1B out of the terrain, too. It has a low-observable design to prevent infrared deflections. (Most people think its low-observable design means just anti-radar.) It also locates its engines below the main portion of the fuselage, preventing infrared lock from most positions except from a tail aspect. Again, ground clutter (while at 50-200 feet altitude) and the location of the engines make it difficult to get into an ideal launch-position against the bomber.
The "33" number of bombers chosen is probably not because of some specific monetary savings. It may have to do with the block of bombers off the production line. The early block of B-1Bs seems to have had the worst track record as far as maintenance and availability. Perhaps they are retiring them for that reason.
Either way, sell them off. Lets make some money back on the whole deal. They can be fitted to only drop conventional bombs by switching out their launch rails; makes them suitable for export. I'd think the UK, Saudi Arabia, Egypt, Isreal, India, Argentina, Brazil, or Australia would be interested in them.
btw - It wasn't just an 11-pound bird that knocked down that one B-1B. Read up on the folly that covered that whole ordeal. It was a big "Murphy's Law" incident.