Medicaid is for poor people who cannot pay for health insurance. It's only reasonable that that includes poor senior citizens who cannot pay premiums for Medicare Part B. Unless you think someone who has the misfortune of being both old and poor should just be SOL.
Seniors need two universal healthcare systems? This country has jumped the shark.
Medicare Part B isn't the problem. Long term care is the problem. People in the lower middle class have to be bankrupted by unexpected medical bills so grandma/grandpa can live long enough to let the LTC providers bilk the taxpayer.
First of all, neither of those programs are universal healthcare systems. One is specifically for elderly people. The other is specifically for the poor.
Unfortunately, there are some senior citizens who are so poor that they are dual-eligible. However, senior citizens as a whole are much less likely to be poor today than they were in the days before Medicare and Medicaid.
I'm not sure what the solution for long-term care costs is. It's the flip side to people now living long enough and medical treatments advancing enough for people to even get to the point of needing long-term care. It's worth pointing out that hospices, which were once strictly not-for-profit entities, have become a cash cow of sorts for for-profit operators.