Thanks for posting this. I hadn't read it before. I agree that subscriptions aren't as useful as zaps. And the idea of your budget is your subscription is pretty cool.

However, I'm still not quite convinced that subscriptions will more or less lose to zaps. Szabo really does hot the nail on the head with the idea that people value their headspace and would much prefer to pay a little extra (even every month) in order to not have to think about trivial charges.

Many cities charge a fee for parking in the downtown area. Imagine if a city had some flat rate plan that let you park in any available spot any time you liked. No doubt it would be very popular unless it was outrageously expensive. But it probably wouldn't actually be beneficial to the city (regulating parking with congestion pricing is kinda handy).