This has been in the works for a while. The mechanism to start accomplishing this was passed in the IRA. Then, it takes time to do the actual work of negotiating.
“We will have tougher negotiation, more competition and much lower prices at the pharmacy counter,” Trump said in a Rose Garden address that was closely watched by drug companies and patient groups. “And it will start to take effect very soon.”
The last administration was content to just talk big and forget about it. The Biden-Harris administration has moved quite swiftly in comparison.