Skipping ads can have a hugely detrimental effect on a YouTuber's income. YouTube doesn't count skipped ads in their payment calculations. Advertisers only pay for ads that people watch. If the bulk of the viewers of your channel choose to skip ads, then this will have a significant impact on your income. YouTubers have to hope that the brands whose ads play on their channel make entertaining or compelling ads that encourage people to play them all the way through.