If the UN Guidelines for Consumer Protection haven't brought down capitalism, why do you think having pre-written T&C that a company can opt to use would?
If anything, having easily understandable pre-written T&C in the style of similar license could only support capitalism: companies would opt to use them if they deemed it profitable, and consumers would be more able to make the informed decisions on which capitalism should thrive.
I also wonder how much cash the companies could save by not having to have lawyers involved in drafting custom T&Cs. One nice thing about GPL is that once a precedent is set, it's more or less followed everywhere. Same here: once the courts establish what this public T&C includes or excludes, it becomes much more clear what a company can and cannot do.
If anything, having easily understandable pre-written T&C in the style of similar license could only support capitalism: companies would opt to use them if they deemed it profitable, and consumers would be more able to make the informed decisions on which capitalism should thrive.