In these companies, you're not asked whether you can afford to save. It's assumed that you will save, no matter how little money you earn. That's the true secret of payroll deduction. You live on what's left of your pay, without even noticing that you've started to save. As a bonus, the company often matches your contribution.
Many more companies are likely to follow.
A few pioneers, such as McDonald's and Motorola, signed up their employees years ago. But most plans started recently, after an IRS ruling that solved certain technical problems. When companies switch to an automatic plan, they apply it first to workers who are newly hired. You aren't getting your new paycheck yet, so you haven't built those wages into your standard of living. That can be a harder sell.