This echoes the old “Buy U.S. Savings Bonds on the Payroll Savings Plan” or the current TSP G-fund available to federal workers. If the regime is correct that only 10% of the workforce eligible to participate in a 401(k) program do so, this is all so much noise as there’s no reason to assume there would be a large participation in this scheme.
No, I think they are saying that only half who are eligible to contribute to IRAs do so (not 401(k)).