its a double-edged sword.
It has hurt in that more people are using things like Google and YouTube to figure out how to do minor things themselves... typically wrong (even 2 decades later, people havent figured out that not everything on the internet is true or accurate). It has also hurt because people use the internet to "diagnose" a problem before bringing their car in, so they have either an unrealistic expectation or a flat wrong diagnosis (see my above statement).

It has helped by allowing legitimate shops to post articles and blogs online to try and dispel the wrong information, and to advertise specials, tips, discounts, etc.

Online reviews are another aspect that seems to be coming into its own. For a long time all you could find about a business was negatives and bad reviews. With more and more people of every generation going online first, rating and review sites have figured out how to weed through the negative and fake reviews.
More people are starting to see the benefit of posting about a business online when they have a positive experience rather than just when they have a negative.
But that also comes with a downside: Almost all businesses now live and die by their online reviews. One bad review (deserved or not) can mean thousands of $$ in lost sales.