Considering these devices should be readily available at this point (nearly a full year from their initial launches) it’s quite odd for them to be so short on inventory. This would lead us to believe that Google is getting ready to retire the Nexus 5 and Nexus 7 as their flagship Nexus devices on the Play Store and make room for the new breeds.
Inventory adjustment also suggests that the new devices will be made available for purchase almost as soon as the announcement goes live, though we’ll obviously have to wait for official word to see if that ends up being the case. Another thing this could hint toward are price adjustments to make the older devices cheaper once the newer ones hit the digital store shelves. The Nexus 5 would still be a fine phone for anyone at a cool $300. The only thing we can advise you to do is make sure your Google Wallet account is up to date, make sure your funds are up to snuff and make sure that trigger finger is ready to fire on the point of sale later today.