We arrived at engines before online chess, and the two have come up together — both being enabled by the growth of computers. You can choose not to use an engine, but it will exist either way because others will choose to use it when it’s enabled by those same things.
To get rid of the engine, you have to get rid of computers — or in the case of Freestyle/Chess960, create so many openings a human can’t memorize them all so only has a short time to prepare.