To me, it's not really a "wait until the big 4". It's moreso that the E has gotten fans into a throwaway mentality where they know the b level PPVs will usually have a shytty build, not to mention the two guys (or ladies or teams) will fight every week before the PPV in some way, then have the exact same fukking rematch the night after the PPV match.
WM builds seem to be slightly better in terms of time to build a feud and overall effort (creatively) that's put into the entire story. It's definitely not always a given, but it's called WM season for a reason.
IMO, when a big match build is done right, such as the entire Reigns/Strowman saga and even Brock/Braun now, it doesn't matter where the match is done. To me it's actually preferable that the goodness is equally distributed across the year like the attitude era.