Yep. Prime vs. prime would be interesting. Jake would definitely win a stand-up fight. He did enough pitter patter striking and leg kicks to get decisions over Woodley and Akiyama...no doubt he'd outstrike Askren by volume. I really don't remember how good Jake is off his back--that would be the main factor. I remember him subbing guys more from dominant wrestling positions. Then again, he did quite well vs. Maia in many different positions. He'd definitely not have to worry about being submitted...while Askren would.
Two fights I'd rather see than this: WW Lombard or prime Palhares vs. current Askren. Lombard judo tossed Shields all over the place when they fought. And he's a serious threat on the feet with his KO power. He was never a great grappler at MW but was very powerful at WW. Against Palhares, would Askren really want to risk being on the ground for 3-5 rounds? Palhares submitted a bunch of wrestlers, including Shields, Fitch, Pierce, Story, etc. He even had Hendo in trouble and Hendo mainly won because he outstruck him...something Askren couldn't do.
In that grappling footage, Shields was the one who got takedowns. He stuck to Askren like glue and didn't allow him to 'funk' Unsure why you would assume Askren would outwrestle Shields automatically. There was a distinct size advantage for Shields too.
Shields was a nightmare in the early 2010s. Askren could beat him, but it's not a given that he will have the grappling advantage automatically.