So, all the things it seeks to eliminate -- fouling to stop the clock, forcing bad free-throw shooters to the line, the winning team looking just to run out the clock to preserve a lead -- would happen at the END OF THE THIRD QUARTER to keep the "pre-ending" score close, or stretch it out, rather than at the end of the fourth quarter.
Think about it: Five minutes to go in the third quarter and you are down 12 points. You'd employ all the tactics you now use to close a gap and have a shot at winning in the fourth quarter in order to keep the game close at the end of the third quarter before the Elam Ending. You'd have even more incentive to do so because now some games are basically conceded by the last 3-5 minutes. But with the Elam Ending, you'd always want to at least try to narrow the score to keep the game alive as long as possible.
The Elam Ending only SEEMS to work occasionally now because lots of coaches haven't figured out how to manipulate it. In the end, it'd have the same flaws while eliminating exciting overtimes and last minute drama. Sounds like a plan created by a subcommittee of bureaucrats in Washington.