Again most people can't afford the up front cost.

Its expensive to be poor, and most people are poor

They are already in debt paying huge amount of interest monthly.

I like being able to charge at home and it's a luxury I know not everyone gets.

For the numbers:

Paying off a $600 charge at $10/month like you suggested would take almost 13 years and cost over $900 in interest at a 18% apr

So you are spending almost 50% more on interest than the original charge. So 150% more expensive at 1500 vs 600.

For a 5 year payoff you have to spend just over $15/month but still are paying over $300 in interest. That's now over $900 total or 50% more expensive because you can't afford the up front cost.

Yeah, that'd be nice if people could take on debt and adjust cash flows like a business, but a lot of people don't have the financial flexibility to spend $600 in a lump payment. That's why people keep bringing up 60+ percent of Americans live paycheck to paycheck. I'm fortunate enough to be able to make those types of purchases a couple times a year, but I know my privilege is not the norm.

The best someone may be able to do is 12mo financing on a new credit card with 0% apr, but miss a payment and its 25% interest. If they even get approved.