What indeed? Prove otherwise... hmm?
The fact that he was a three times world champion and was leading the GP? Had set the fastest lap in qualifying and had pulled out nearly 7 seconds and was still pulling away? Sorry, if that race had gone to completion, Senna would have not only won the race but possibly lapped everyone up to 3rd. Only five cars were on the lead lap at the time of the accident.
http://www.grandprix.com/gpe/rr551.html
I think my belief is not only well supported, but proven with fact.