Made in USA goods are just as affected as imported goods right now. Tooling, some raw materials, equipment all have some or all of their parts being sourced from various places in the world. Made-in-USA still uses plenty of Indonesian, Japanese, Indian materials/parts. Just look at the automotive sector: Korean chip-makers can't keep up with demand, and ECU's can't be made fast enough causing a shortage of new cars.
Not only all that, but lots of folks were forced to stay home from work for 2+ months last year, and plenty of labor left the market because their stimulus checks got them just as drunk or high as their paychecks would. Then there were ongoing issues of reduced labor capacity (forced capacity reductions in many regions), loss of employees due to fear or life changes, people changing industries or simply leaving their state for a multitude of reasons. Many of those folks would be the ones casting, machining, assembling your made in USA goods. Meanwhile, as PST said: demand is ever higher, because plenty of people were able to keep a paycheck.
Short story is we've had limited materials, limited labor, and a huge spike in demand for going on 12 months now. It's no surprise that lots of things are hard to get right now.
It's likely to get worse over the next 4-8 months, and it will be a VERY slow re-alignment back toward normal that will likely take a couple years. IMO it's a perfect opportunity for smart companies to decouple from regimes hostile to our existence.