That would be a valid criticism if the statement had been "many public sector pension schemes are" or "many public sector pension funds are". But there are easily enough people entitled to pensions under either the universities scheme on its own or the local government scheme on its own to count as "many", let alone under both of them together.

In fact there are about 4.25 million members of funded public sector scheme, as against about 5.5 million members of unfunded schemes (active, deferred and pensioners), so about 44% of public sector pensions are funded.

Peter