It was a long while before I got a job that offered a 401k match. A couple of the other jobs had one, but they were crappy, high fee plans. So I saved on my own in a Roth, because for a while my income was in the range you cite. I worked for an employee benefits broker for a few years, and pitched plans to a fair few blue collar people. One objection some had to participation was that (they thought) it showed Management they didn't really "need" the money and so it'd blunt future raises. In some places, this view was not entirely unfounded- including my own office. Others mentioned large child support payments. A fair few 401k plans out there have high fees - especially if it's a small business. The small businesses where I worked had high fee plans, no match, so why the hell would I want to save with them? If you've got a low salary, unless you are living with your parents, you're unlikely to make your full IRA contribution, much less have anything to spill over into a 401k.
If the plan has low participation, then the higher-paid employees/owners may be limited in the amount they contribute to their own 401ks. Someone already mentioned diverting raises to a 401k contribution. But in a place that can't afford a 401k match, cost of living raises are not a given, either. Even so, 1% of 30K is $300. If the org can't front $25 per employee/month into a 1% match (auto-escalate contributions, not necessarily the match, later)... should it be all that surprised if the employees feel they are too pinched, as well?
Or, depending on your benefits package, others may want to focus their pennies on a short term disability plan. Prioritizing the most likely/urgent risks is still rational.