Seems more likely that the cause is that RTS isn't a popular genre among gamers and Beyond All Reason is obscure[1] even among RTSes. There's no fame or money to make it worth investing in cheating.
[1] Among the general public, not RTS aficionados. Which is unfortunate; Total Annihilation and its spiritual descendants like BAR deserve more love.
People have been banned for cheating, so cheats exist.