Nowhere did I day sales = better product and I never would.I disagree. The job of a musician is to make music. The job of radios and the music media is to sell music. There's plenty of music out there that is a better product than Nickelback's music, that does not sell as well as Nickelback does. That doesn't mean that Nickelback makes better music.
If you want to espouse the idea of more sales = better product, then I could point out plenty of your arguments in threads about guitars and amps to convince you that yourself might have a point.
But a professional musician pays their bills by making music. If you are signed to a big label it's quite literally your job to sell music. When you don't do your job they fire you aka not continuing your contract.
That's how the business works. You want to make hits because it works in your favor to do so.
These days musicians make their money off of tours and merch..BUT a hit song is how you make that happen. If you've got a hit on your hands then hopefully that means you'll make enough that the label and all the little folks get their money out of your release, and you've made enough to see money from it. That money also goes to funding tours, buying merch, etc.
The entire point of a single is to catch people's ears so they are interested in what you do. A single is essentially a commercial for your band. Any marketing will tell you that a commercial is only effective if it catches on.