Because they would have to possess technology that doesn’t exist in order to circumvent actual encryption without a key.

If I adequately encrypt my own data, and keep the keys a secret, I could hand my hard drive off to Microsoft and they could spend billions running all their AI clusters trying to crack it, and it would be a futile endeavor.

If the government had the technology to bypass encryption or quickly and inexpensively crack it, they’d use it for a whole lot more than unlocking smartphones. They could basically control the flow of Bitcoin on a whim with such tech.