Here is Publishers Weekly‘s March 15 story by Jim Milliot.

It is not even spring yet, but the expected printing crunch already appears to be in full swing. A lack of both workers and paper continues to hamstring printers, and a number of independent publishers have already reported finding it extremely difficult—if not next to impossible—to find printing time as far ahead as July and October.
To help all parts of the book business’s supply chain get a better handle on what is going on in in the printing world, the Book Manufacturers’ Institute has begun a new monthly survey of its manufacturing members in order to assess capacity and lead times for softcover and hardcover books. The results of BMI’s first survey were released yesterday, and did indeed indicate that press availability is at a premium.
The survey is divided between printers of hardcover and softcover books, with responses finding that printing capacity is currently running at more than 80% for both formats. For the 17 hardcover printers, the average manufacturer was running at 85% of their capacity. (Capacity was defined as what you could manufacture today based on all variables.) The average lead time for completed hardcover books was 84 days. For soft cover books, capacity was at 89% and the average lead time 70 days, based on the 15 responses received by the BMI.
“Labor and paper are still the two biggest factors we are seeing in book manufacturing today,” BMI executive director Matt Baehr said in a statement.” Both can be very difficult to come by and that is affecting a large majority of our industry.”
Casting yet more gloom, Printing Impressions passes on to us international concerns about printing paper supplies as expressed by the World Print and Communications Forum. Demand for print in general is recovering, but supply problems put constraints on the industry’s ability to take advantage.
Given that book sales are going so well despite all these supply-chain problems, I begin to wonder whether it’s really such an awful problem after all. If a publisher can’t get their latest book printed by July, they reschedule publication to October. If they can’t get a reprint of one of their books, then orders will accumulate, or prospective buyers will move on to some other book. It’s not like people are turning up at bookshops and finding bare shelves — there are lots of books. And as everyone kind of knows and understands about the disruptions caused by the pandemic I think there’s a great deal of patience out there in the form of a willingness to wait until this or that book finally becomes available again. The real inconvenience is to the publishing companies: they now have to work harder than they’ve had to do for forty or fifty years or so to wrest books out of printing plants. Welcome, you youngsters, to the way it was in the dim and distant. Assumptions, schedules and systems need rejigging. Annoying perhaps, but far from fatal.
One might have expected that supply-chain delays would have lead to a switch-over to ebooks, but this doesn’t seem to have been happening. Will we, the book-buying public, eventually get fed up of waiting and give up on the print book? For myself, I’m betting the problems will be over before many people make that jump.