I believe the horse is well and truely dead. But whipping the corpse causes a reflex twitching which some can mistake for proof of life...And again, this is EA, the horse is still stumbling around on its legs so it can carry on getting a flogging
The titles most guaranteed to sell huge quantities must be either NFS Underground 3, or NFS Most Wanted 2. Don't try and reinvent the wheel; just give us more games with that formula, with a bit of a graphics update.