Bill Gates saw computers and extrapolated that there would be one in every home, Gordon Moore produced Moores Law which literally extrapolated compute in the 60s and almost still holding, and you can extrapolate that GPT-5 will perform better than GPT-4, and that there will probably be a GPT-6 that will be even better than that.
Extrapolating that technology will get better in the future when it has got better in the past isn’t a sure bet, but it’s a reasonably reliable one.