If you think back about Řstberg's 2017 season, he was often on the pace, but had some issues that dropped him. Rear wheel bearings broke numerous times, from a part that was made stronger in the M-Sport cars. Also some hydraulic/electronic issues which plagued M-Sport only early in the season. Also, had he continued in 2018, the car would have started to lack upgrades that the M-Sport cars had.

At most, I can see some hobbyist/gentleman driver using the C3 WRC's, but no one with a competitive target.