How do you have socialism without government ownership?
Easy.
For example, if cars are polluting to the point it becomes a health hazard, then you pass laws to regulate and restrict how much pollution they can emit.
You get the responsible result you want of safer products, without government actually owning the companies.
When the democratic republic regulates business, the same goals can be reached without actual public enterprise ownership.
But public ownership also can be much more efficient.
For example, in WI, there is a need for drivers for garbage trucks, school buses, mass transit buses, snow plows, etc.
So in WI these are all public.
That way, when it snow, then bus drivers report to garbage trucks that have had plows attached, and away they go.
Costs a lot less, and is very flexible.
School bus drivers are also regular bus drivers, so keep up their skills.
By being able to switch roles, then you can load balance much easier, without having to have so many extra people on the payroll, for reserve.
They also do very efficient things like use the garbage incinerators to produce steam that they then pipe to all the downtown businesses, for free heat.
Very useful in the cold WI winters.