If I lived before the tape measure was invented, and rely on carefully placing my metersticks to measure things, I can get really good at measuring without the need for a measuring tape. After all, a measuring tape is just a few flexible metersticks anyways, so if you need to measure something longer than the full length of the tape, you are screwed.

If you take the measuring tape away from the person who relied on that tool instead of being good at using a meterstick, or perhaps no tools besides their own arm length, they are gonna suddenly not be able to measure, unless they go through the effort of learning to measure without the tape.

You can argue that measuring tape is a crutch preventing people from learning how to properly measure, and has its own limitations, but regardless its still really helpful, especially for people who only need to measure things occassionally, and not super long things.

ChatGPT is a tool. Just like all other tools, like computers, cars, etc., if you take it away, most people cannot perform the function for which they relied on the tool to help them do.