Lets consider the following Guild Hall upgrade …
War Room Restoration 1 > Scribing: Minor Supply Drop
This requires 50 “Heavy Supply Bags”.
Looking at www.gw2spidy.com the pre-expansion Buy price was 6.16s and the Sell price 9.50s.
These bags were obtained from either the centaur camps in the Alpine borderland maps or via the Krytan Region Track in PvP.
Since the expansion, well we have no Alpine borderland maps and well surprise the current TP sell order depth shows 308 orders with prices of;
4 @ 3g 99s 99c
1 @ 9g 99s 99c
304 @ 10g 00s 00c
Now if I am mistaken and there are other spots to gather Heavy Supply Bags please accept my sincerest apologies, but the TP price movement sort of answers that question.
I could go into the effect on the small to medium guilds resulting from the general expense of Guild Hall upgrades; the effective removal of WvW upgrades from the game due to the burden of having to re-upgrade your guild albeit now through huge expense, the consequent delay, and the effect of this on the WvW player experience.
Once more I think Anet has fallen prey to Form over Function.