Normal is variable.
In the 60s, 70s and 80s, it was normal for shops, stores and warehouses to have abundant supplies on hand. Manufacturing facilities might have had a 6 month supply of parts. No deliveries for weeks? No problem, just keep making stuff.
Then the bean counters got involved. Why pay for all this stuff so far ahead and all the space to store it? Go Just In Time and get only the stuff in that will be used and gone in a few days. Don't worry about deliveries, they'll come and if they don't, we'll just save money by sending the workers home and turning the lights off for a few days, or weeks.
Blame who you want, but it all falls back on the bean counters, the C Suite monsters that value stock price above all else.
The cargo ship is another issue.
Why are there so few ports to take them in and offload them? OK, some of it is geography. Not all of the US coastline is suitable for it. But that's not true everywhere. And then there are the Unions that hold far too much power in too many areas. Unions can be good, or they can become overbearing and an impediment to progress.