1) We were in the middle of a massive trade war with the whole world, so it was already very hard to get a lot of stuff into and out of the country
2) The rest of the world people believe they should protect themselves so they do not want to let people going everywhere, some nations prefer not to let high risk travelers in and as a result experts / workers / money / raw materials are not going around like before.
3) People are buying up a lot more than before because they are working from home, or cannot travel so they are buying toys instead of taking vacation.
4) Everyone is printing money so everyone with cash is spending, buying stuff, moving to a bigger home, moving further away, etc now instead of let inflation taking its toll.
5) Some MBAs believed just in time inventory is the key to profit but they forgot others who didn't cancel order earlier were getting ahead, keeping their inventories and orders so they have stuff to sell (see Toyota, they stockpile chips since Fukushima instead of cancelling chip orders like the Domestics, so now Toyota has a lot more chips and a lot more cars they can sell).
6) Social distancing at work place and travel restriction, things are made slower.
7) Some people decided to retire instead of working because they think everyone is getting abusive and aggressive (money is secondary as this is happening everywhere even when they are not getting unemployment benfits)
I'd say this about covers it! Working in the production end of the bike industry, I'd say all of the above is spot on. The trade war with China already complicated things in ways not expected (or just wasn't that well thought-out). I didn't move the supply chains to the US, it just moved them to different parts of SE Asia--parts that are not nearly as well-equipped to handle a pandemic as China. Travel
within Asia has been really difficult, never mind traveling to Asia, and there have been numerous delays within various SE Asian countries, many of which have been trans-shipping goods from China (partial assembly in CN, finished assembly somewhere else to avoid the tariffs). Supply chains are complicated, and dealing with the trade war bent them pretty hard; this on top of it has just broken them.
A couple of additional things: weather: the inordinately hot spring and summer in CN has led to a lot of factory shutdowns/slowdowns throughout the country, as many of them are only operating a few days a week. This is due to an electricity shortage brought about by 1) a deliberate move from coal and 2) higher consumer demand due to the extreme temps they've been seeing.
shipping: whatever you read about the problems with ports, containers, accidents at the port of Taichung, the Suez back-up still having an impact... It's all actually true. It's impossible to get containers, and when they finally do arrive it can be at a 10 times what they normally cost. Yes, 10 times.
Lastly, lots of folks as me "why don't the factories just ramp up production"? It's not that simple. In part because China, Taiwan, and some SE Asian countries have pretty rigorous social benefit programs that have to be paid by the employer--and once you hire someone you have to pay these benefits for a set period of time. And a lot of the factories view the increase in demand as temporary. In short, they don't want to scale up production and incur significant mid-term costs, just to have the rug pulled out in 6-12 months.