What happens if the government does not reauthorize the EB-5 reginal center program?

Nothing quick for Indians unless you qualify for EB-1A. Usual route is with an employer offer and then labor certification and in the queue awaiting a visa.

There are many options besides EB-5. There are EB-1 for top people, EB-2 for masters and EB-3 for others, but EB-2/3 are backlogged for Indian nationals subject India quota. There are also family-based visa options including immediate relative and F2A, spouse of permanent resident.

I would imagine some class action lawsuits to get pending cases adjudicated, but no new ones will be taken in.

Hopefully the U.S. Congress will authorize the grandfathering in of all pending petitions regardless of whether the EB-5 Regional Center program is reauthorized.

There are no quick ways to residence through employment for an Indian national. Perhaps consider direct EB-5?