I don't think it's arguable that Efren's prime was after he turned 44 years old. Yes, Efren won lots of events in 2003-10, but many of those events didn't exist or didn't have strong international fields before that time period. So all this shows is that the opportunities for titles increased as Efren got older, and that he had extremely good longevity, not that he was in his prime in his late 40s and 50s.
It's true that Efren learned 1p and banks later in life, but that's also because these were more niche games, played mostly by Americans, when Efren was younger. If Efren had learned these games when he was younger, he would have dominated then too.
This is why I don't think it makes much sense to compare Efren's greatness as an all-around player to today's players by looking at DCC MOT awards: players like Fedor, today, grew up in an era where all the top players were playing every game, and had tournaments like the DCC to compete at for their whole careers. Efren grew up in an era where top international players didn't compete in 1p or banks, and the DCC didn't even exist. If it had existed when Efren was 20, and there was prize money to be won, can anyone really imagine he wouldn't have at least a few more MOT titles?