Guess I'll throw my hat in this ring.
Having a cap on wireless service, with overages above it, deters usage. Having a cap on wireless service, with throttling above it, does the same thing, to a lesser extent. When you're running a 10x10 700-upper-C LTE network with large cell sizes in urban environments, you need to deter usage. When you're running a 10x10 or 20x20 AWS LTE network (with the associated smaller cell sizes), backhauled by whoever's cheap and available, if a user can get service, you really can throw capacity at the problem and it will work. So you offer cheap plans with low-priority network access in congested areas, and more expensive plans with higher-priority network access in congested areas. Sprint's closest competitor, which is still losing subscribers, is doing exactly this.
Sprint is in a different situation. Right now, they have 5x5 LTE carriers covering an area slightly larger than what T-Mo's AWS does, on average. They are more coverage focused than TMo, but less so than Verizon and AT&T. The operative word is "right now" though. Fast forward to a year from now and they'll be able to overlay, say, 15MHz of additional downstream capacity over a smaller area than an AWS site and push subs with newer phones onto that. You'll see these overlays more often than you would in a normal situation because SoftBank has a vested interest in getting TD-LTE in 2500/2600 out there.
So, what does this mean for capacity now? Well, it's still somewhat limited, but not quite limited enough that you have to purposely deter usage on the consumer side. Fast-forward a year and the need for network management only arises between the time Sprint realizes it needs BRS TD-LTE on a site and the time it deploys it.
Getting back to density for a moment, how many subs are on a crowded PCS sector at this point? We aren't talking about at a special event...just normal usage (at a special event you won't be streaming Pandora). Let's say there are 200. Take a worst-case scenario and have 70 of them streaming Pandora at 192 kbps. Also, take a pessimistic case of cell capacity being limited to 25 Mbps overall due to signal issues (that's two-thirds of maximum, roughly). You have 11 Mbps left over for the rest of the subscribers, assuming 70 people streaming Pandora for awhile. AJ, let me know if there are more than 200 users on a crowded, urban PCS cell at a given time, or if my other ratios seem off.
Speaking of Pandora, its default is 128 kbps, and unless you pay you get that for, at most, 100 hours per month. Assuming cellular-only usage, that's 5.76GB. Just a data point here, nothing more.
I would actually argue that Sprint is launching shared business plans to provide businesses with an apples-to-apples comparison of their services with that of their competitors. When you're using a phone or tablet as a business item, there are certain things that you won't do, particularly if you know your plan is capped. The fear of overages without an unlimited plan is mitigated by the fact that data usage on a business device is, more or less, a cost of doing business. And you may have an "IT guy" who tracks data usage and makes sure things are squared away in that respect; you don't really have that on the consumer side. So, while consumers want unlimited, many businesses, on a mobile connection anyway, can work around capped plans. Or they can go with unlimited plans, since Sprint still offers those.