Last week, Valve decided that it was time for the Steam Controller to be retired, just over four years after it launched. To get rid of the last of its stock and give people one more chance to snatch it up, Valve shaved the price down to £4/$5, which was a steal, even if the controller wasn't all it was cracked up to be. Unfortunately, it looks like the remaining stock has run out before the orders have been fulfilled.
People reported that they'd received refunds out of the blue, even for controllers that had allegedly shipped. Following that, Valve informed customers that it "mistakenly took more orders than [it was] able to fulfill." Unfortunately, since it's not making more of them, it can't just wait for more stock.
The Steam Controller is officially dead, then. Along with the Steam Link and Steam Machines. Valve launched its bid to take over living rooms only four years ago, and now the whole ecosystem it developed has been shelved. Steam Machines were the first to go after they caused not even the slightest splash at launch, but none of the products really gained much traction.
I still use my Steam Link, but even with a wired connection I have trouble with plenty of games, while my Steam Controller has been ignored for years. I was so enthusiastic when I got it, but it felt cheap, it was too noisy and it turns out that replacing the right analogue stick with a trackpad is a terrible idea. Both were attractive prospects that didn't live up to their promise.