I'm speaking from a relatively n00b position here, having only played a short way (three missions) into the campaign, therefore maybe my udnerstanding of teams is off, but being on a team would mean that you win and lose as a team and cannot break your team, yes?
If that is the case, then should the AI instantly be gifting me every tech it researches, and in turn be unafraid (and there be no negative consequences) of asking for gifts? My Altarian allies occasionally offer me things, but since in at least one of those missions we were a rather than allies, shouldn't they have been giving them to me the second research was done? They should also research different stuff to what I'm researching and then request (assuming I haven't given it) a gift of every tech I research.