>What happened? I thought computers were supposed to be empowering? In all the techno-euphoria of the 1980s, Brand and others did not consider the manufacturer’s intent: our everyday computers, tablets, and phones are consumer machines built for consumption. The personal computer was replaced by the consumer computer just as soon as it arrived.
No. This isn't one thing. Three things happened concurrently:
1. Networked services
2. Malware
3. Copyright maximalism
The first trend is close to the "consumer computer" concept, since it's basically the old mainframe business model warmed over. However, the other two trends greatly accelerated the handcuffing of users.
Copyright maximalists feared the scourge of casual piracy and wanted to ban consumers from having access to copying technology. They failed, but Congress let them have protections for DRM that effectively amounted to being able to opt-out of being copied. They also sued and lobbied for intermediary liability on network services, requiring that they effectively do on-demand content removal.
Malware did exist in the mainframe era but it was mainly prank programs. Personal computing dramatically extended its reach. Proprietary software vendors were able to condition users to execute programs they could not inspect or modify. They also attempted to prevent copying with DRM, but an active cracking & piracy scene stymied that. So people were now blindly executing modified applications, often times with obfuscation to prevent removal of cracktros[0]. Pranksters used and abused this to distribute malicious code along with their software.
Network services made malware worse, too. The point of entry for malware in the Don't Copy That Floppy era was infected disks; and the solution was to write programs to detect and erase them. But with the Internet, everyone can connect to your machine, and it turns out that not only creates an entirely new class of software vulnerability to spread malware with, but a new motive for doing so - exfiltrating information and reselling it.
So you have three cycles running together that has made actually exercising anything resembling "freedom" into a scary ordeal. Computers just "get sick" with "viruses" and start stealing your information, so people rush to centralized services, upon which copyright maximalists have demanded control over and largely gotten it. "Consumer computers" are not (entirely) conspiracy of big tech to control our lives, but an act of convergent evolution under particular pressures.
[0] Object analysis complete. Target is a Space Pirate Crate. Space Pirates, strangely, dislike theft. The only way into their crates is through use of force.