Recent statements by Steve suggest he thinks he can still do it. I think that's probably a bit too optimistic; he's around 8000 miles below the cumulative average mileage and about 5500 miles behind Tommy's curve. With 179 days to go, that means he needs to average around 30 miles a day more than Tommy, or about 250 miles every day for the rest of the year. If he follows Tommy's curve but does that 30 miles a day more, he'd need to be doing something well over 300 miles a day now. That just doesn't seem likely.
If, on the other hand, Steve restarts the challenge on some date in the near future, he has to either equal Tommy's daily mileage or hope he can significantly beat it through the winter period to allow a more achievable target in the remaining summer months. That seems a lot more do-able - he was about 3000 miles ahead of Tommy when the accident happened. An out-of-the-gate daily figure of 220-230 miles a day from, say, 1 August followed by a winter of 180-200 mpd, then racking up next summer to 220-230 again would see him past the 75k - but, as you say, not necessarily beyond Kurt's total!
It remains fascinating whichever route Steve decides to take, and I continue to wish him all success.