Definitely agree that the overall downturn will be worse than dotcom or credit crunch - this is truly global and effects every sector directly or indirectly.
I expect that there will be a general lack of demand for anything high production and high cost (eg top end BDX, prestige champagne), but that might not filter through to massively reduced release prices as many owned by luxury goods groups who may have the firepower to throttle supply to ride it out. However, take a look at 2008 BDX EP prices, six packs of 1st growths were ~ 800 GBP. 2009 was through the roof from there but had a bumpy ride up and down over the past decade.
On the other hand, I can’t really see release prices on small production wines (eg top Burg) reducing at all, it is all over-allocated anyway and a great deal cheaper than the secondary market.
I guess auction prices and broked prices of back vintages will be the place to pick up bargains (cf today’s market), but always need to be careful trying to catch a falling knife. If buying for drinking soon you don’t need to worry what will happen to prices after you have consumed.
Don’t underestimate currency effects, UK stored wine that is IB looks cheap to the rest of the world right now, but prices will go up when a merchant must restock later vintages at current FX rates.