I've spent thousands on ads and have overall made 5-13x in ROI.
I can say that my bad ads get less sales than my good ads.
My good ads consistently work, my bad ads don't.
So, ad copy matters.
However, a good advertiser accepts that not everyone is a good ad target.
You may not be a good target for advertising.
I would say, I'm not a good target.
Some people are very moved by advertising.
Others are not.
The 80/20 rule applies here.
80% of the profit in advertising probably comes from 20% of the target population for a given product.
I've learned that it's better to think of good advertising as just a form of communication.
A great ad is factual information that answers questions customers have, and provides urgency.
An ad might contain some fluff, but to really sell it usually needs to state explicit, accurate facts, in easy to understand language.
There is a lot of bad marketing from people that think they can make an ad just because they're a hip or a cool person, or they have an eye for color.
Those ads can be egregiously bad.
Just as some marketing sites are all fluff no substance, but sold to unsuspecting business owners, the same happens with advertising.
But the key idea is that, for certain products, good ads sell "enough" to the target audience to be very lucrative.
A great book on this topic is "Ogilvy on Advertising." Specifically, the first chapter.