The BIG problem with your argument is during periods where the economy is strong the price of tickets is also "firm" therefore its' a bad time to buy and if you have to purchase tickets for cash there will generally be more sales and discounts available in during economic downturns.

In general I think BA have the balance wrong at present. There's an implicit assumption that the points are reasonably useable and offer significant value compared to buying tickets. If they become too hard or too expensive to use, as ThatT1Feeling said the customer perception is increasingly shifting to see avios as a waste of time so the value of the scheme to BA (and its credit card partners) must also dropping.

It will be interesting to see if they address this or if hubris convinces them they must be doing something magic and their results aren't being flattered by the economic upturn combined with reduced competition. Time will tell but I'm old enough to have seen a few cycles....