Middlemen exist because it is not obvious to middle-class Americans that they need to know what the relevance of Dafen is to getting a painting done and because most middle-class Americans do not speak excellent Chinese, and most Chinese painters presumably do not dream at night of putting down their brushes and opening up an SEO consultancy.

Instapainting captures customer demand and transforms it into a servicable and fully-paid series of work orders, to painters (and firms employing them), for the thing they want to sell. This has value. Media depictions to the contrary, artists do not enjoy starving.

If you feel strongly that this model is exploitative, you can apply corrective capitalism by making your own website, doing your own SEO, selling your own paintings with fulfillment by your own outsourced team of painters, and compressing the margins. I wish you the best of luck and skill in this endeavor, but if you model your business as being viable at 1% or 5% above COGS [+], I will warn you that your first year in business is going to be a very educational experience.

[ + ] Cost of Goods Sold; an accounting term for the expenses of the business which directly represent fulfillment as opposed to e.g. marketing, engineering (this company sells paintings, not software, so software isn't COGS for them even thought it might conceivably be for SaaS), or business overhead.