Imus was advocating for Opie's being on WABC when he was still around. I'm certain he did get offers.
The thing that's fascinating about Opie's career is that he was the "radio guy" of O&A. He went to college for communications, started the way a lot of us did. He wasn't a standup or bringing the same thing to the show Cumia did, but he was the "anchor" that kept things moving and more of a student of the medium than Anthony. Yet Anthony at least in the short term (possibly because he was so polarizing and leaned into it) seemed to do better post-radio with his Compound Media stuff and Opie seemed to flounder with his projects and not get much traction.
In terms of his comments on salary/revenue sharing, I gather that Opie wasn't foolish with his money during the glory days of O&A, but he has two kids. There's assets and there's expenses, and being a parent isn't cheap as your kids get closer to college especially. So if he's saying look, WABC is offering me some ridiculously low figure, or low base, then you calculate the revenue sharing isn't even putting you in the low six figures once you give the agent his cut, it's very possible the numbers don't look great. Anthony's a single, no kids guy who moved to South Carolina and sold his "compound" so maybe being back on being a political guy on WABC is worth it to him. Different lifestyles, different personalities.