Income taxes can be made progressive. Sales taxes are almost always regressive. Businesses need to do a lot more paperwork to document these taxes.
Why don't leftist parties campaign to abolish sales taxes and replace the lost revenue with an increase in a progressive income tax?
Am I missing some critical functionality of sales taxes that income taxes cannot replicate?
Edit: Here's an important feature of sales taxes that a few commentators helped me realize. It's better if we think of a sales tax as a "revenue tax" instead. Let's say we are in a country with multiple provinces. A business sells stuff in province A. However, the business and its owners are both located in province B. If sales tax didn't exist, then all money earned by the business would go to province B's government. Province A cannot enact tariffs and stuff like that. Thus, it puts up a "revenue tax" that is taxed to business for all revenue earned, i.e., a sales tax.
For those wondering, no, a corporate tax is not a revenue tax. It's a tax on profit. Non profits for example, do not pay any corporate tax, but they do pay sales tax (which is basically, revenue tax).
Usually in the US items purchased for resale are tax-exempt. A restaurant, for example, would have a resale certificate on file with their suppliers. Any food, beverage, and disposables they get would have no taxes since they are expected to sell those to a consumer. Cleaning supplies, however, are outside the bounds of their resale cert, so they would pay sales tax on those items.
Also, sales tax is not remitted to the government instantly in the US. I think it's done quarterly, but I'm not exposed as much to that side of it.
USA is different from the majority of the world on this by having an actual old school sales tax. Other places have value added tax instead. The difference is basically purely administrative. In both cases it's the final price at consumption that determines the actual government income.
By instant, I mean monthly or quarterly. It's still much shorter than the annual company tax which itself is only a pre-payment of the owners income tax which would occur several years after the income transaction was made.