What are some possible reasons for the high failure rate of alliances?

What will be an ideal response?

Most economic theories assume that, left to their own devices, individual entities will behave in their own
self-interest. The success of an alliance, of course, depends on the willingness of partners to subordinate their own
interests to those of the alliance, but even when partners start out by suspending self-interest, circumstances can
change dramatically over time, compromising even the best of intentions.