My opinion is this...
People's mindsets would be different if they had uncapped from the get-go. Let's say that when Telkom launched ADSL, they decided that the accounts would be uncapped. Everyone using the internet then would have had the mindset of 'Hey, I've got the internet... And it just works. If I want something off the internet, I'll just download it when I feel like it'. So, would there be a few users that would download as much as they could, just to have it? Yes. But they would be a minority. Every country in the world has these guys.
Instead, they imposed a scarcity mentality on us. So, instead of me thinking of it as something that I can access whenever I want, with little cost, I need to check my usage stats. Make sure I don't go over my threshold. Make sure that I get my money's worth by downloading as much as I can at the end of each month. If I want something off the internet, I check with my buddy first to see if he has it before getting it, who had to download it. So, when uncapped comes along, hey, I gotta download the crap out of it. Get everything while I can. Push the downloads to the max, so that I get my moneys worth.
With decent prices on uncapped, this mindset will eventually change. Who cares if I don't use the internet for a week or if I haven't used up my GB's by the end of the month? Who cares if I decide to download 70GB of stuff I need this weekend? Why download all the "Ubuntu ISO's" just in case i need them and I might run out of bandwidth by the end of the month. I'll just download the ones I want. Usage will eventually drop off for most users. ISP's will then be able to cross-subsidize the big downloaders with the guys like me that will probably push a maximum of between 10 and 50GB a month. For me, a 200GB 'fair use' limit is fine... I doubt I could find that much stuff to download each month. I understand there are people who can though, and that's fine as well... I'm sure there will be services which they can use, and pay a premium for. For people like me, 200GB is virtually uncapped. I'd imagine that for most average users, this too is the case.
At the moment though, with uncapped being all new and shiny, I'm hitting that line as hard as I can. Why? Same reason starving people gorge themselves on food when they finally get it. For years I've had to watch what I do on the internet. I've had to buy topup's and plan my youtube browsing sessions. I've had to have backup accounts in case I got capped. I've had to ration family members and staff. Now, I'm free to do whatever I like. Of course I'm going to run around like a kid in a candy store. But, the novelty will wear off, and in a few weeks time, I'm going to be back to normal habits... and so will (almost) everyone else.