As also a native german, I have to disagree in turn. Story time:
In the 90s, when the Internet started to come into popularity, me and friends were desperately trying to get a connection that didn't cost money per time unit.
For the longest time, with no free local calls like the US had, that simply did not exist, at least via dialup. One option was a "Standleitung", which was almost literally a permanent landline between you and your provider, same signaling and all. Only small providers would usually be talked into it, but then you had to pay a (at the time) huge monthly fee to the Post/Telekom because the line took resources away permanently. Some few people were lucky enough to be able to establish radio channels with their provider (this was long before WiFi was a thing). At one of my first jobs, I got ISDN "callback" as a benefit, which meant that I could call the router, hang up immediately, the router would call back and establish the connection, company would pay!
Finally, after what seemed like an eternity, the first few flatrates appeared. Stay online as long as you want, download as much as you want (at speeds that were still measured in kilobytes/second, but completely adequate for the time). It was definitely Unlimited.