For the owners of such remnants of gone away times, it's a real challenge to keep such things afloat.
Plain maintenance is expensive and does not bring satisfaction.
Opening the park for the public is expected by the 'outside' world but would push the costs even higher.
Very luckily this estate seems a very convenient place to function as 'show ground' for garden fairs. Such fairs are organized twice a year: every second weekend of May and of October.
At once the efforts made for the maintenance get a meaning and the place gets a function. Even better: the owner gets an occupation and, for a good part, the maintenance gets a source of finances.