There have definitely been changes over the decades in institutional attitudes regarding early entry and grade skipping. Back in the 60s and early 70s, most districts had an established system for determining who could early enter K/1 or whole-grade skip, with no particular obstacles to using it. But then, most districts also routinely retained students who were learning disabled. So obviously social skills and developmental level were not highly prioritized in either direction at the time.
(And I also effectively skipped fourth on a school change, into a school that placed students by low-mid-high across two grade level clusters--so effectively four-plus possible placement levels for any student in the cluster.) One of the unintended consequences of mandated state-wide testing has been flattening these different options, as schools focus more on making sure as many students as possible meet expectations on the state test. Allowing double-promotion takes high scoring students out of that grade's pool, and potentially lowers their scores in the receiving grade from advanced to grade-level, which is disadvantageous to the building's accountability numbers.
So social skills are not the only factor even now.
Frameist, the data indicate you are not alone. Research on grade acceleration overwhelmingly finds that most who were accelerated would do it again, despite any negative sequelae, and that most matched peers who were not accelerated regret that they were not. (Of course, there are always exceptions, whose experiences are just as valid for them, but these are the group data.)
