[tacojuan]

Data isn't a scarce resource, bandwidth maybe, but data conservation is not (should not be) a user "incentive".

Carriers acting like data is scarce and in need of conserving are discouraging users from using their product...

[wtallis]

Gigabytes/month is strongly correlated with consumption of the actual scarce resource under the assumption that most users have similar usage patterns. Variable pricing based on peak times and places would be too complex to actually work well for cellular data, unlike time-dependent pricing for wired broadband or electricity.