Unlicensed bands typically have the requirement that you implement some kind of backoff or collision detection mechanism to ensure fairness between users of the band and guarantee you are not sending more than X% of the time. I don't think LTE is prepared to do that at all.
Plenty of other unlicensed band users don't do this. Even bluetooth and wifi typically don't avoid eachother on 2.4G, with the exception of transmissions from the same device.
And of course all other unlicensed band users do this. Again, this is a regulatory requirement. And ultimately, it is not just that you need to ensure others have access to the band, you also need to be robust in the face of persistent high interference given the number of users in the unlicensed bands. It's not a good fit for default LTE.
ISM is the only that doesn't do avoidance (where it has primary status, like the 27MHz band).
If course it doesn't blast excessively, but it's also not mandated to shield to death.
