As someone else said, re: Oklahoma. Nebraska previously played in the Big Eight without any Texas teams. They still recruited Texas in the past.
Perhaps their non-recruiting of Texas could have something to do with their coaching change and the hiring of a guy who's career has been predominantly spent on the West Coast?
Recruiting is about relationships. Look at where Mike Riley has coached and look where his recruits are from.
This is how we ended up with a who's who of All-League Connecticut players before we smartened up and cut off our PP.
Man this OU losing Tx recruits if they join the BIG debate because of Neb's downfall debate is getting old. Most who comment on it are either too absolute on a point, or lack the details. Some finer points to consider:
No CFP or BCS system during Nebraska and even OU's peak of success. I dare say CF history, that is crowned national champions, would be very different had the CFP been introduced say in 1950.
Let's not forget that during the OU-Neb era of dominance, segregation had ended in the SEC (South in general) but expansion wasn't settled & recruiting and program building, esp with the local recruits, many being Black Americans, was still new. History has now taught us that de-segregation took at least 10 years to translate into positive success for the southeast in general, and it was really the non-SEC Florida schools, that cashed in (Miami and FSU).
No more partial qualifiers for Neb, which started before they joined the BIG.
No Tom Osbourne or Barry Switzer equivalents - please don't say Stoops is on par with Switzer, he is not. Could he get there? Doubtful, he's had his chances and age is becoming a factor. OU has mostly gotten blown out in major games the past 7 years.
OU vs Neb was a guaranteed game in the Big 8, not so in the Big12. Thus if Neb beat OU during the Big8 days, they essentially won the Red River Rivalry as well. So Neb's decline is also not a shock considering their biggest rivalry basically ceased when joining the Big12.
OU will lose Tx recruits if they leave for the BIG, esp if Hook Em ends the Red River Rivalry, but they'll still be much closer to Tx than Neb. But let's not forget that OU has & will likely continue to lose the once mighty inroads in Tx because other FBS programs in the Longhorn state are no longer doormats - this was bound to happen. Look at how many NCs fbs programs in Florida have won - 3 major powers in that state. Tx will inevitably produce a handful of contenders in a given year due to their high school football culture and ding, ding:
aTm is now in the SEC, which is huge not only for them, but other SEC schools. The SEC unquestionably has the greatest state by state footprint for high school football talent now, well they did before annexing Texas. Just as kids in Tx will consider aTm & its conference mates, kids in Ga will think hard on aTm - conference reciprocity - ma, pa, family and friends will still get to see my on tv.
Expansion has changed the game, albeit such has been going on for decades. But in this hyper media, instant results-expectations age - OU & Neb have dealt with direct major changes unlike most of the SEC, Pac12, BIG and even traditional ACC power programs. One joined a conference where the traditional powers have remained solid (BIG) & on the way out, it was ugly - so were the other departures, Colorado being the exception. OU remains in a fickle Big8 - SWC shotgun marriage, where brand and identity remain issues - which leads to my next point.
The Big12 needs to cut the run and gun spread & minimal defense crap, this league wide style is not NC worthy, esp against a typical SEC team, as well as the top shelf programs from the ACC, Pac12 and BIG - where typically the best team in a given year runs a combo of spread and pro style offense & defense matters. Big12 football is bad for recruiting in general.
Could OU succeed in the BIG? They will likely get to the CCG most years as the west representative, but it won't be easy. Wisconsin and Neb aren't pushovers for anyone. Moreover, they'll likely lose to the likes of OSU or Mich, much of the time. Harbaugh and Meyer look to be around for a while. OSU has one of the great high school football states and Michigan has been recruiting nationally with greater success than OU & for a long time mind you. Both Mi and OSU have a greater local pool of recruits than OU - much bigger population.
OU has always depended on Tx recruits and the Red River game, but again their Tx recruiting has gradually slipped since joining the Big12. So it would be unfair to to say the BIG was the cause of diminished Tx recruiting if future membership was on the horizon. This decline already started for OU.
On the other hand, OU has so much history so a game changing, young coach could get them back on track in any conference. (Yes I have written off Stoops).