In fact, the registration process is the least of the problem. It’s merely a once off process. From a technical standpoint maintaining a log of SMSs is a very resource intensive process. It’s going to be very costly.

Imagine the list of resources you have to prepare to implement this process:
People: Technicians and clerks to do data maintenance and archiving.
Hardware: Servers and storage media needs would be very high.
System Design: How to actually do this in a systematic way.

I think you’ll start to get the drift.

All this (theoretically) because some politician got a few hate SMSs. What a crybaby.