If Hyundai are really hungry for Manu championship, if they don't get it this year, they know their biggest problem is Tanak in a Toyota.
Makes sense for them to sign Tanak and take away the threat of their biggest rival.

It may upset Neuville, but he would just have to come out the blocks as best he can as soon as the season starts and try and dominate Tanak who would be having to adjust to a new car, to lay claim to no.1 driver.