[whypretend]

When an eSIM in a phone is provisioned to a carrier, with some plan, usually it does have a phone number and could send and receive SMS.

Though yes you are correct, if you're only thinking of a single chip (eSIM) instead of the system it usually goes in yes, you are be correct - those systems can currently exist.

iSIM, integrated eSIM with SOC (cpu, gpu, ram, wireless baseband, eSIM) will eventually be more common in phones.

Look up: "remote sim provisioning"