The fact that you see pension savings as the property of the company seems "greedy" to me. I'm not criticizing you. It's technically true in at least some companies. Similarly, the Social Security Trust Fund is the property of the US Government, not the future beneficiaries.

The moral failure is treating a retirement fund, and the people whose livelihoods depend on it, primarily as an opportunity for personal enrichment. Pension assets do not belong to the company in the ordinary sense. They are held in trust for the benefit of employees and retirees. The employer generally cannot withdraw funds while the plan is operating.

Wall Street was released in 1987, and the law regarding pensions has changed since then, in part to address employers reverting pension assets. As I understand it, there is a now a 50% excise tax on reversions, which are only allowed in specific circumstances. I imagine this tax is intended to discourage reversions.

Personally, I don't understand why any of the money I put away for retirement belongs to anyone but me. Usually such funds are managed by finance companies, not the employer, and the finance companies are already getting their cut, any lucky excess should come to me.

(The substance of the issue with overfunded pensions is itself a complicated separate topic, which I don't mean to oversimplify.)