Are the new IITs such as IIT Patna good for a secure future?

Yes, the new IITs like Goa, Patna, etc provide good future prospects. However, you would like to consider these points.

• Don’t go for the new IITs that don't operate from their permanent campuses as infrastructure and facilities play an important role in enhancing your academic environment.
• You will face lesser competition in the new IITs during placements and the companies visiting are almost similar to the old IITs. Thus new IITs increase your chances of making it into a good company.
• Old IITs enjoy a good prestige and thus have better ties with foreign universities thus making it easy to get LORs to do foreign internships or higher studies. 
• Old IITs are better for girls because the rules in new IITs are not well established and are in the developing stage so girls usually face a lot of restrictions here.

Now it is up to you to decide