There's a variety of spread offenses and, at a very minimum, there have been variations of what you may consider the spread run in the SEC since Urban Meyer implemented it at Florida around 2005... about a decade ago. And I suspect-- since Mullen was Meyer's OC-- that Mullen has been running a variation of that spread at Ms. St. for a few years now.

And then there's Sumlin, who I think runs a spread/Air Raid type offense since he took over 3-4 years ago. And if you consider those Air Raid offenses spread offenses, they have been in the SEC before Meyer brought his version to Florida a decade ago.

To the OP: There hasn't been as much speed discrepancy in the past as people generally assume. There are some SEC teams: usually LSU, UF & maybe/arguably Auburn, Bama & UGA that have been faster than most other teams. The SEC has been top heavy and the rest of the SEC, while perhaps slightly better than the average teams of other conferences, hasn't been that much better or faster than the rest of the country.

This year, both Ole Miss & Ms. St. had the good fortune to field experienced teams when both LSU and Bama had good, but not dominant teams. And Arkansas-- which makes a SECW title run every few years-- had a really slow start but finished on an upswing. So, the perception became that every team in the SECW was a contender... which ended up being a stretch.

Bottom line, because the Ms. schools-- which I've never considered to be among the faster SEC teams-- fell off at the end of the year after their experience allowed them a fast start doesn't mean the SEC has become marginal now. And Wisconsin plays an SEC team in bowl games frequently and always plays well in those games. SEC teams rarely-- if ever-- blow Wisconsin out. And Ohio State & Urban Meyer are consistent winners, so I don't find that result surprising either.