The website claims that Nissan (the guy)'s business existed before Datsun became Nissan. I think there ought to be some kind of prior art for trademarks as well

The website claims that Nissan (the guy)'s business existed before Datsun became Nissan. I think there ought to be some kind of prior art for trademarks as well. It is not fair that a business suddenly not be allowed to use their trademark (even if they fail to register it) just because someone else registers it.