That's not true , they probably could maintain or update , but what's the point given they'll never likely see another race day there again through no fault of their own.
Levin doesn't have the facilities to run their own racedays and would require considerable capital investment to get up to scratch. Arguably they struggle to maintain what they've got as it is.
Meanwhile Otaki has to maintain all its facilities and rents to Levin for three days for peppercorns.
I have no opinion on whether it is archaic or not however even that model wouldn't generate enough revenue for Clubs to pay their way unless they had significant sources of other revenue.
Clubs have got by on voluntary work and community donations in services and kind. Hell that is how Hokitika kept going. My own father through his business invested thousands in his local racecourse because it was his passion and hobby. That sought of generosity is diminishing rapidly for many valid reasons.