How can we keep Medicare solvent?

It doesn't make sense to me that Democrats want to keep throwing money at a broken system like Medicare when it's obviously going to hit us like a truck when the baby boomers retire. I also don't get how essentially turning it into a voucher system for people 55 and below would work either, since it doesn't address the fact that people 55+ are going to soak up Medicare, pushing us further into debt. Why not reform it for everyone? Make the seniors sacrifice a little so us young folks don't have to foot the bill while getting nothing in return when we retire. Neither parties seem to care about future generations. We simply do not have the money to pay for all these entitlements. You can cut defense and raise taxes all you want, but we are facing tens of trillions of dollars in unfunded liabilities from entitlements that will place an insurmountable burden of debt on my generation, and that is where we ought to start if we want to get serious about this debt crises. Where am I wrong?