Maybe the TTC should think of introducing some kind of 24hr, 48hr and 72hr limited passes that can be loaded onto the card for days when a user might be using transit intensively. (Back in the 70's and 80's, the electro-mechanical ticket vending machines in most major European cities were issuing just such single and multi-day paper tickets. The TTC never made it into those decades, ticket vending machine-wise.)
Day passes are coming to Presto in the form of capping; what that means is once you've spent $12, or whatever the "day pass price" is, any further taps will be $0 for the remainder of the day. This is likely to be based on calendar days rather than 24hr periods, like the current day pass. This is actually an upgrade--with the current day pass you have to go and get it in advance, if you're just going around and you suddenly need to take extra trips you'll pay more, whereas Presto capping will mean you "automatically" get a "day pass" when you need it. And it works in reverse, if you buy a day pass but only ride 2 or 3 times you've wasted money, with Presto you don't have that risk.
48hr and 72hr passes are not likely to come. If you ride a ton for 3 days, you'll just get the daily ~$12 maximum on each of the 3 days, exactly as you would today buying 3 day passes (but with the above named advantages).
Weekly passes may or may not be coming, they're more nebulous at this point. I had heard that they would likely come via weekly capping, where after 3 or 4 "day passes" or equivalent spending across the 7 days, you'd pay $0 for the rest of the week; but more recently I heard they might do more traditional "load a weekly pass to your card in advance" system, or forego them altogether in favour of just the daily and monthly passes.
It would certainly be nice for some people to have a "pass" for hundreds of different possible periods of time, but it would get confusing for both riders and the TTC at some point to have so many different "fare products", even when they're virtual rather than physical. Already, on presto with the TTC we're looking at senior, adult, low-income adult, post-secondary student, youth, and child fares for: single rides, daily passes via automatic capping, weekly passes TBD via capping or loading, monthly passes via loading, annual MDP-type paid-up-front bundles of 12 monthly passes; and potentially tap in+out/on+off, timed transfers, fare by distance, fare by zone, fare by vehicle type, fare by time of day/day of week, fare by congestion/crowding, event fares, etc.