He was jumped by 6 people with no warning. He hit the ground at 20mph. Try crashing your bike at 20mph and see how quickly you jump up and start fighting - not going to happen. Options are limited at best and considering the situation things worked out pretty well. You can buy a new bike. Coming back from the dead isn't likely going to happen.

Here are the rules.

1. Escape - Flee, run, crawl, hop. Whatever it takes.
2. Fight back and escape - If rule #1 is not an option use this hybrid rule.
3. Fight dirty - Yes, it is ok. The dirtier the better. The crap on tv is worthless.
4. After you escape let the police deal with everything. Put it behind you as you will likely never see them again and living in the past sucks.

If you are going to carry pepper spray, keep it on your person. Try the Kimber Pepper Blaster II. You can easily keep it close and it has very good range. Sorry this happened and from what I have read you did everything right.