How much does SIM-locking (i.e. adding a PIN to lock it) mitigate the risk in your experience? I understand that if the telecom service dept. is compromised it'

How much does SIM-locking (i.e. adding a PIN to lock it) mitigate the risk in your experience? I understand that if the telecom service dept. is compromised it's useless, But in a low-effort social engineering attack are the telecom personal trained to suspect the lack of PIN? Phone numbers are like social security number or at least a parallel identity where I live, Banking to vaccine happens through 2FA auth(Often only through it). Recently banks have started to advise SIM-locking to prevent SIM jacking; My cries to support hardware tokens have been in vain so far. What's funny is SIM-locking was quite common during pre-smartphone era, I think the Nokias of those time even asked for a SIM-PIN with each reboot; Even then the customer service would just reset it when you said you forgot it. I don't think it would be any different now, after-all they just ask your name & address to confirm identity. It feels like SMS based 2FA + Oligopoly Telecoms are a disaster waiting to happen.