What you say holds merit. Still, until a few years ago the Pac 12 did not have a TV contract. I noticed that once they began broadcasting Pac 12 games woman's recruiting improved and transfers began to head back west. The loss of Direct TV just happened recently. As to regional stations that is true if you watch only through network providers like Comcast. If you watch Pac 12 online with any provider for regional access. I watch Pac 12 through Sling TV during basketball season. They give you access to all the regional games. I am sure there are also many other services give you regional access. Most teams now days also stream games that are not being shown on national TV.
The attraction for viewership for recruits is not so much national coverage, rather just that friends and relatives can see them play. Now that is available via streaming so playing locally or for previously high profile teams who were usually nationally broadcast is not a factor anymore. Players families certainly have access to watch their kids play across the country for more programs than ever before.
I think your last paragraph is probably spot on, and in that regard the PAC has improved.
I don't do the internet broadcasts much, a rare Rutgers game. Since I don't have Sling or another service I can't access the PAC12 network at all, as my "broadcast" provider is DirecTV. I will make a minor correction to your post - DirecTV never carried the PAC networks. Could never agree with the PAC12 on a contract. Thought that would change when AT&T bought DirecTV, but it didn't. And before the PAC networks, local Fox stations would carry some PAC 12 games; ultimately, that was what got us to go with DirecTV, the availability of the various local Fox affiliates that were not blacked out for women's sports and were, for a time, prime carriers of women's basketball. Before streaming and all the conference stations. Now, while we still have DirecTV, it is primarily for NFL Sunday Ticket since we relocated to AZ and want to watch the Giants. Not so much on the Fox stations anymore, although the Big 12 still has contracts with them.