The jammed control theory has 2 weak points
1) the a/c is a fully coordinated diving turn down to 2 feet between wingtip and grass, when it's already way too late to recover. If you have an aileron jam, you would notice the turn becoming uncoordinated (smoke detaching from the fuselage) at a much greater height, because you get your independent right rudder input responded by the a/c, but no response to the aileron input. There is no sight of anything like that.
2) Jammed controls typicall result in an uncontrollable high speed, high angle impact with the ground, with small impact crater radius. On the other hand, crashes due to misjudged height above terrain result in high speed, but low angle collisions with the ground, resulting in the long trail of debrish along the crash path. This crash fits into the latter category.
For me it's more interesting, why the pilots made this mistake. I have seen a MiG-23 crash resembling this one. High speed flying towards spectators, perpendicular to the runway, and high bank turn in the last seconds. The result was similar, that aircraft actually bounced from the ground, engine fire occured and crashed 1 km away eventually.
So somehow this type of crash is intrinsic to, "coded" into the manouver. If you turn early, it is not spectacular enough, you can't scare the crowd. But if you turn late, you lose more altitude than originally planned, gain higher speed in the process. Turning at that point will require more than the usual control forces, higher G loading etc. The safety rules say that the aircraft cannot overfly the crowd, but in case of the pilot already making the mistake and missed the regular point of turning parallel with the spectators, it would be actually much safer to allow the aircraft to stay level, climb and fly over the spectators.