Let's give credit where it's due. Declaring that 'Thursday Night Football' is actually better than the football played during literally any other NFL time slot is flat out preposterous and nothing short of insulting to anyone that tuned in to watch even one game in which teams in bright, gimmicky jerseys tried to overcome the limits of the human body by competing on three days rest. That being said, the commissioner whose actions are so consistently laughable that he's basically become a walking, talking parody of himself did use the word "almost".
I don't know what barometers other than 'viewership' and 'quality of play' are measured, but I would venture to guess that every single one of them is working heavily in favor of continuation of a mid-week game whose sole purpose is to take advantage of the viewing audience's undying love of the sport. I can't even begin to comprehend what advanced analytics Roger Goodell and Co. are using to determine that 'Thursday Night Football' is actually a success, but they must be pretty convincing because they go in complete opposition of the results of the eye test. Maybe they just twitter searched the hashtag #TNF and considered every instance in which a person got bored with bad football and decided to mock it through sarcastic social media posts a victory. With the amount of times I hate-watched Brock Osweiler on a weekday, their product had to shooting through the roof when it came to drawing the ire of the internet.