IMO it all comes down to money. They no doubt get a bonus for breaking a WR/world best. For now they can break a road WR with relative ease compared to a track WR.
Once these guys can run o12:37 or i12:49 or 26:17 you can almost certainly guarantee they try to break those track records and cash in on the those bonuses.
The (relative) ease of breaking a road WR over a track WR will remain in place and will draw talent to road WR attempts instead of track WR attempts until:
A) the road WRs are at (or get much closer to) the quality of the track WRs [note 1]
B) there is a spike /shoe usable on the track that matches the benefits of the Nike carbon plate shoes [note 2]
C) distance races in track gain as much popularity/marketability as road distance races
Note 1 - the i5k WR is 12:49.60 which is seemingly very close to the 12:51 Cheptegei ran. But an indoor race of 12:51 is harder than a road race of 12:51 for a few reasons. Firstly the nike carbon plate shoes no doubt help. Secondly Cheptegei has more experience racing roads than he does indoor track
Note 2 - I am not completely clear on the development /availability /advantage of Nike carbon plate spikes in relation to the Nike carbon plate shoes. Or if the shoes would be beneficial on a track? or an indoor track? Would they be more beneficial than the best available carbon plate spikes?
For posterity here is a race video: