I'm not sure the 'contracts' have changed much in the last 40 years - I recently thinned my collection of old T&C booklets (sniff, sniff) after doing one last cpmparison with the latest versions for several cards. All had the clause along the lines of 'provide advance notice in writing at least X days before taking affect'.This moving of the goal posts is rampant at the moment. So many institutions are executing their "right" to change their T&C's whenever they see fit, it's seriously hard to keep up. I remember back when contracts were actual contracts and the whole point of them was that THEY COULDN'T BE CHANGED. I know that concept seems oddly quaint like something your grandfather would come out with either right before or after the words "Back in the good old days…", but seriously, what is the point of a contract for credit if it includes the clause that the terms and conditions included can be changed at any time without the agreement or approval of both parties?
Surely such a clause immediately dissolves the contract from being an actual contract, or else the very definition of the word contract has changed so dramatically as to not actually mean the same thing anymore. I guess it's a bit like traffic lights, where green, amber and red used to mean go, be prepared to stop, and stop, Whereas now green means go, amber means go faster, and red is nothing more than a suggestion.
True, the number of days may have dropped slightly but they're still typically well over 30 days.
I think what has changed is the ability to make money out of CCs now that the half-hearted attempt by the RBA to stop fee-gouging as well as the change to the issuers being able to freely attempt to turn you into a credit addict with unlimited 'increase your limit' offers. The amount of psychology used against customer was phenomenal.
Creating a 'revolver' was the aim, make you addicted to spending without thinking about how you'd pay it off saw seasonal analysis of every card user. If over the previous 2 or 3 years you typically increased your monthly spend in July (perhaps booking Xmas holidays) - then you'd receive an offer to increase your credit limit in mid to late June by around the proportion your monthly spending had increased from June to July in previous years.
If accepted within X days then you'd receive follow-up limit increase offers of smaller amounts. Again, depending on how many days it took you to respond would determine how soon (and how large) the next offer would be.
All designed to get you hooked and to get to the point that you can no longer pay off the balance each statement period.