It's not that China's blocking shipping, it's that retailers aren't confident that they can move a product at whatever the previous cost of the product x 2.25 + other costs and profits was, right?
A lot of telescope parts are made in China, IIRC, so let's use them as an example. Celestron is based out of California, let's say they sell a scope for $1400 and it used to cost them $800 to get from China. That means that to make the same amount on each unit after the cost, they'd need to charge $800+(800*1.25)[the tariff]+(1400-800)[their margin on the product] for a total of $2400. Mind you, I have no idea how thick their margins really are, so I'm not going to comment on that. Now, my understanding of markets is that they sell at whatever they think the market can bear, so if they thought they could sell the scope at $2400, they already would have been. So, it makes sense to just not buy any telescopes just now, since if dingus wakes up tomorrow, declares victory in the trade war and declares tariffs woke, you'll be stuck with a bunch of product that will be basically impossible to move without taking a loss. This also gives you time to scrape up the capital to buy at the increased price if the tariffs don't drop. Eventually, though, you're either going to have to buy product at the higher price or close up shop.
So much to say that I'm a little surprised that there aren't at least some shipments coming of lower-cost higher-volume goods that might be better able to absorb the shock of the tariffs. The fact that there's just nothing coming our way is incredible to imagine. Is it because of the recent gouge-flation; companies have recently increased prices to the resistance point and they now know that there's zero wiggle room for passing those costs on to customers without suffering a loss in sales volume?