You say that like it’s a bad thing. You can still use Bluetooth even when your phone has a headphone jack, and headphone jacks can be IP67 rated so it’s not a concern for waterproofing.
I mean, the only other rating above that is IP68, and that would require them to specify the depth and time that the phone can be submerged. Most manufacturers only go for IP67 because it’s much cheaper to test.
Nah, not a limit. It’s just a cost/benefit trade off. Manufacturers don’t typically push for IP68 unless they’re specifically marketing the device for underwater use, and believe users will be willing to accept the higher resulting cost.