Might direct insertion make a Mars landing more competitive with a Jupiter flyby, energywise

Direct insertion into Mars orbit has been practised already:
http://en.wikipedia.org/wiki/Mars_Global…

It appears to be quite effective although time consuming to get the final orbit.

Competition between missions is based on many factors such as cost, estimated number of citable papers that will be published, scheduling of assets such as radio telescopes, and (these days) on the publicity value of the mission.

Cheers!