Why are psu's so squeezed in supply? Is it due to the coronavirus factory shutdowns?
A number of things caused a domino effect.
The virus broke out right after Chinese New Year. So nobody could get back to work. Even after the factories were allowed to open up, it took a long time for the supply chain to all fall back into place. So even if you have healthy workers to assemble PSUs, you still need the guys to make the capacitors, the heatsinks, the ICs, etc.
So NOW the supply chain is back in place and you can build PSUs, you have to get that product out of China.
Good luck!
Freight typically ships under passengers in passenger jets. But with fewer passengers, there's fewer flights. And what flights there are, they're stuffing full of medical supplies! So while it used to cost maybe $5 to ship something (as part of a larger order, of course), it now costs 10x that!
So you use FedEx, UPS, DHL, etc. jets.... Well, not only is that typically more expensive, but now you have to take the products out further to a port that supports those carriers since they're not at every airport. Example: Fedex only has 12 hubs including their Memphis facility. You have to take that additional transportation cost and time into account now.
So you decide to put the product on the water. More expensive than usual, but still cheaper than air freight But a ship from China to the U.S. takes four to six weeks! And when the virus hit and those boats came back into port, they didn't turn them back around with more cargo like they usually do. They closed the ports and quarantined the workers! So for a long time there's been fewer boats on the water to move the merchandise!