Right, no-one cares that the website of the plumber in your town looks the same as that of the plumber in the next town, because those guys aren't competing with each other.
I'd go even further. No one cares about the website of the plumber. Full stop. People find the plumber on Yelp!, Google Places, Facebook and other business profile pages around the web. None of those require any design work to bring in business.
There's still a disconnect on the part of some small business owners...they think that their website is important. But a lot of them are realizing that nearly all of their inbound leads are coming from other sources and that the website is just an expense that isn't really necessary.
Just for a counterpoint, about a year ago I did a landing page and accompanying marketing campaign for a friend of mine who runs a small landscaping business in Pittsburgh. With Squarespace and a couple days spent on a branding strategy, his site was head and shoulders above any competitor.
After a small investment on his part in advertising, we were generating many more leads than he could handle at a very good ROI--seemingly because the nice site was doing a good job differentiating him. So at least in his case, having a decent website did bring a real competitive advantage.
FWIW, my observation came from working on a scheduling product used by ~40k small businesses. I think what you've noticed is just how successful advertising can be. We've seen clients have similar success with Facebook and Yelp! ad campaigns, all without a homepage. One customer got over 30 new customers (expected LTV of over $1k per customer) in one month of Yelp! spend.
Exactly, web design agencies should pivot or include (and heavily promote) ad management.
I got to see the numbers of a mid-sized web design agency, and they were really an ad agency, but they didn't realize it (and didn't market accordingly).
There's still a disconnect on the part of some small business owners...they think that their website is important. But a lot of them are realizing that nearly all of their inbound leads are coming from other sources and that the website is just an expense that isn't really necessary.