Could you explain how clothing needing to be cleaned is relevant to subscriptions? After all, you don't have to buy the cleaning products from the clothing manufacturer. Same for car tires, etc. So the clothing companies and car companies aren't making any extra money from this.

I agree with your original post. Very thoughtful. The subscription version of glasses is contact lenses. Plus, most people need a tweak to their vision prescription every year (or two), so they need to update lenses.