NFL is it's own thing when it comes to ASG games.
Any comment section or social network today will be flooded with "I never watched the game" while saying how they've always liked the "skills competition." Another example of places like twitter not being a good gauge of things like this.
6-7M still watched the Pro Bowl, which has been awful for years. Less than 1M watched the skills competition, which real people care even less about. Less than a mil for anything "NFL" is horrible. A pretty wide gap, ratings wise, from skills competition to ASG, which doesn't exist in the other Big 4 leagues. Why I said the NFL is it's own thing. With NHL, NBA, MLB, the audience is similar with a little uptick for the actual ASG from the skills competition (HR derby, All-Star Saturday Night).
Looking at most recent viewership for each:
MLB: HR Derby got 6.9M, ASG got 7.5M
NBA: Saturday Night got 4.2M, ASG got 6.2M
NHL: Skills got 1.1M, ASG got 1.2M
NFL: Skills got 866K, Pro Bowl got 6.7M
One of those is really not like the other.