I agree.
Prior to Trump, Fallon was the king of late night and they were talking about replacing Colbert with the Carpool Karoke guy.
Fast forward to Trumps presidency, Fallon (albeit this was a many months ago, and I do not super follow late night host ratings) is now sitting in 3rd behind Colbert and Kimmel.
Just look at SNL. They had no one to do Obama or least do a funny Obama because Obama is bland. The best one I saw was the Rock doing Obama, and that was not funny because the Rock was so much like Obama, but funny because the Rock was trying to be Obama. Much like Tracy Morgan's Mike Tyson, it was a terrible impersonation, but funny because it was so out there.
Trump is loud, Obama is calculated. IT is easier to make fun of the loud guy, because he gives you more material.