You are releasing new versions of MC so fast.
what we pay, if we wish to be up to date, seems to be a "subscription", but...
I work in an IT department and if I forget to renew any subscription to any software (Microsoft, Oracle, VMWare, etc.) I need to pay based on the years I forgot to pay.
The upgrade cost to MC24 should be based on the version we already have. You are asking the same money upgrading from a 5 year old version or from MC23... it does not matter.
having purchased the MC23 licence a few weeks ago... it is quite a non sense to pay again to be up to date, according to me
so sorry...