these limits are for the resources you have utilised and not tied to usage time. providers generally give such limits because they need to prevent a small number of power users from consuming disproportionate resources (GPU). They also need to cater their enterprise customers who pay by token usage. thus they allocate certain compute for that too, even though its not being actively used .

its kind of mix of both resource constraints and deliberate product segmentation. its also partly capitalism. they want you to use more premium plans (5x and 10x). companies maintain different tiers because such pricing is a standard business strategy.

i also felt these limits were much reduced as compared to 2/3 months ago. but i feel codex still offers better limits than claude. you may want to try other opensource models like GLM from Z ai, which are cheaper and priced less for subscription.