The whole blocker to micro payments were banks and credit card companies (same reason ACH is so archaic even though other companies have much better systems--they decided it's not in their interest to improve it). Credit cards have a flat fee, plus a percentage. That's why small businesses have a minimum purchase price (even though it's against their merchant agreement).

When it first started I figured PayPal would have enabled microtransactions, but I gave up on that years ago. Venmo could, but it doesn't seem like that's the market they're focused on. Bitcoin would fill that niche, but it has a few other barriers.