It's no risk to the reseller. They were already paid to relinquish the plot.
The risk is all on the "buyer's" end since they have to compete against all the other players who want the plot. Available plots don't go unnoticed for hours. The housing discords update their lists hourly. The plots only appear to be ignored because few players are interested in camping during the initial hours when the plot is extremely unlikely to have the timer expire.
What displaying the timer would do is make it easier for the reseller to attempt to purchase multiple houses on multiple worlds. They can set up a list of when houses on multiple worlds will be ready for purchase then switch between characters a few minutes before the appropriate time to try their luck against the other players present. One plot gets purchased (regardless of who gets it) and they're able to switch to the next world on their list. Right now they're hobbled by uncertainty on when the right time might be, making it harder to juggle attempts to purchase multiple houses especially across multiple worlds.
It's hard to say whether displaying the timer would result in resellers getting more houses. They'll be able to attempt to purchase a lot more houses but they'll also be competing against a much high number of players at each house.