It's definitely a different world now so I'm going to give you a hedging, waffling sort of answer.
If you look at Hill's career from 1962 and beyond you see that he did really well on the track but that he was never going to be Ron Clarke or Mohammed Gammoudi or Ian Stewart. If he was going to win anything major, including national championships, it was going to be either at the marathon or in cross country. The same was true for Hogan and Higdon (to a much lesser degree.)
Hill's championship games (Olympics, Euros, BCGs) choices were to be either one of the better but not best guys on the track or to concentrate on the marathon.
Ritz has other options. If he's discouraged by his early results in the marathon he realistically can think of himself as a track guy and decide to focus on the 5,000/10,000. His 5,000 time could convice him that he is even a possible medallist on the track and that may push him away from focusing on marathons (which would not necessarily exclude running some out of season marathons for the money.)
That said, he has planty of marathon potential and to steal a point Nobby likes to make, even his fast track times may not mean he has enough of a kick to win a madal at the Olympics or Worlds.
I think he could do what Hill did at the marathon if he commits to it. BUT, I doubt that he will do that unless he has a race in the fairly near future that encourages him to focus on the marathon. I don't think that anyone with his track potential would spend seven years, like Hill did, or anything close to that length of time working on his marathoning seriously when there are other things he can do well and profitably.