64GB configurations are currently estimated for delivery in 1-2 days in the United States and several other countries on Apple's online store, while same-day pickup is now available at dozens of Apple's retail stores.
Back in November, shipping estimates for the 64GB model fell back to 4-5 weeks. The estimate began to shrink gradually in January and has now improved enough for next-day delivery to be a possibility again as of this week.
Apple never provided a reason for the shipping delays, but it may have been due to a recent shortage in the NAND flash storage market.
Apple TV 4K was released last September in 32GB and 64GB sizes for $179 and $199 respectively in the United States. Apple recently began selling refurbished units for $30 off in the United States, a roughly 15 percent discount.