Wrong.  You are over thinking this, and throwing out a lot of assumptions (throwing longer passes, defense playing harder/softer, playing slower.  You really think, with under a minute to play, a team is going to play “slower” if down by one score instead of two????
Would you agree it is easier to score 2 times than 3?  Or 1 time instead of 2?  Of course.  But you keep harping on missing the 2 point conversion if a second score is made. Irrelevant!  If you go for 2 after the first td and fail, you have to score 2 more times in the final minute.  After recovering 2 onside kicks.  The odds of that happening are minuscule.  If you kick the xp, you only have to score once (and make the 2 point conversion).  Still long odds, but much, much less than needing 2 scores. 
The odds of making the kick are much higher than getting the 2, thus making it much more likely you will only need 1 more score instead of 2.  That is why you take the (more or less) “sure thing”.  There is only a minute left, remember.  Your scenario may be plausible if there were a couple of minutes left, or if you had timeouts.  With less than a minute left and no timeouts, you are going to try to score as fast as possible whether you are down 1 score or 2.
No, the correct decision is to kick.  And the vast majority of coaches and experts agree.