If a tree falls in a forest and no one's around to hear it, does it make any sound?
And here's a twist for you. If your site has an accessibility bug and no one complains, is it really a bug?
I mean, think about it. Your website is sleek. It's shiny. It's on brand. And it works perfectly for you. You have no complaints about some inaccessible menu, or from users who cannot distinguish between links and surrounding content, or anything about forms not working.
So your website has no bugs and is accessible to all, right?
Wrong! Just because you can't see a problem doesn't mean it isn't there.
Did you ever notice people smiling to you awkwardly at a party? You chat them up and you get some forced smiles and weird stares? Go and check a mirror. You might have some spinach in your teeth. Everyone noticed but were too polite to tell you.
If a tree falls in the forest, it will make a sound, even if you yourself won't hear it.
And just because no one complains about accessibility on your website doesn't mean it's accessible to all.