Location is very much a factor in things like total application volumes and specifically ED volumes.
Not sure why you think that.
In their last available CDS, they got 588 ED applications, and only accepted 260 (44%), rejecting 328. That behavior makes no sense if they are overly concerned about filling their class.
OK, so then they were apparently targeting a total class of around 864. They probably yielded around 250 out of ED, so that implies they had about 614 enrollment slots left for RD.
They then apparently had 10009 RD applicants. That’s a lot of applicants. They admitted 2775 of those (27.7%), which implies an RD yield of around 22% (I think this is for all schools). But still, that means they rejected 7234 RD applicants.
So Oberlin does not in fact have a problem getting enough applicants, nor is it in a position where it cannot still be choosey in both ED and RD.
By the way, I happen to have recently done similar numbers for Wesleyan. It got 1047 ED applications, which is obviously a lot more (+78.1%), and admitted 424 ED (40.5%, so not so different), which probably yielded around 410 ED. It enrolled 743 students, so it only needed around 333 students from RD. This right here is one big difference between Oberlin and Wesleyan: Wesleyan gets a lot more ED applications, so even at a similar admit rate ED, it has far fewer enrollment slots left to fill in RD.
OK, then to fill those 333 estimated slots, it had to admit 1672 people RD, implying an RD yield of around 19.9%–actually lower than Oberlin’s! But again because it got so many more ED applications, it has a higher total yield than Oberlin.
Just to finish things off, it got 13,474 RD applications, so a good chunk more again (+34.6%). Despite the lower yield in RD, because it needed fewer people to enroll ED, and it got more RD applications, it had a much lower RD acceptance rate (12.4%).
Point being, yield dynamics are really not so different between Oberlin and Wesleyan. But Wesleyan gets more RD applicants than Oberlin, and a LOT more ED applicants than Oberlin, which leads to a much lower RD admit rate. But still, Oberlin is not struggling to enroll its classes, it just has to admit a higher percentage of a smaller RD pool to get there.
And yes, again this is very much in part a function of location. Indeed, I am pretty confident if Oberlin was in Connecticut, it would have very similar application volumes and admit percentages.
But its RD yield would likely not be any higher.