I too think it could be done relatively quickly. You just have to switch to pace instead of power (offer power for footpods) and start with a few plans.
At this point you don’t need to swing for the fences…there ist zwift and nothing else. And Zwift has no workout creator, the plans are meh and they only supports training peaks workouts based on distance.
At the moment I have to re-edit my time based workouts to distance, matching the timed intervals to meters. And Zwift only allows intervals as a multiple of 200 m. So no fun at all.
But I make do, because there is no alternative.
I’d wager at some point in the future there will be a big enough market for this kind of product. If you could position your company in front of the pack with little effort, this seems to be worthwhile to me. Especially since triathlon is a part of TrainerRoad already. So it’s not really stretch to do something like this.
And in the future smart treadmills will be the norm, not an outliere.
But on the other hand, if it’s not in the plans for TrainerRoad, I hope somebody else will do it.