No, many of them are not. As an EE who does his own supply chain mgmt at a startup, I've been in crisis mode for a couple of months now. Some components are not available at any store, at any price, for the next 6-18 months. Had to make design changes to roll out prototype hardware.
I wouldn't trust anyone outside of Mouser of Digi-key if my job depended on it... for a one off, why not, but not something when a few failures is going to end up costing more than the profits for the run.