What Goes on in Castle Vufflens?

This is Chateau Vufflens in Switzerland, which is impressive and famous enough that small versions have appeared in various museums of miniatures, and you can download instructions on how to duplicate it in Minecraft.

And yet the thing is privately owned and never open to the public. What do the owners do in there?

I would expect there to be lots of rumors about the Grandmaster of the Bavarian Illuminati or some such, but there isn't even that. Nothing. Just an enormous beautiful castle that must cost half a million francs a year to maintain. How can they afford it without charging admission to tourists? And what is in it? The only pictures I have found are of the large watchtower; not a word about what goes on in the rest of this enormous edifice.

The spot was fortified by 1100, when the monastery of Romainmôtier entrusted it to a knightly family that came to be known as Vufflens. In the twelfth century the castle was the center of a nearly independent domain. But as order returned to Europe in the later Middle Ages, things got harder for these independent knights. The first well-documented owner of the castle was a certain Peter Vufflens, who became a vassal of the Bishop of Lausanne in 1175. The bishops transferred the overlordship to the Counts of Geneva, and they gave the lordship to the Cossonay family, reducing the Vufflens family to lowly sub-vassals.

The Cossonay clan wound up on the front lines of a 50-year struggle between the Counts of Geneva and the Counts of Savoy over the Canton of Vaud. At first loyal to Geneva, they were eventually forced to transfer their allegiance to Savoy. Count Peter II of Savoy then arranged a marriage between the heiress of Vufflens and one of his own vassals, named Duin. The Duins held the castle for nearly a century. Then in 1390 an heiress of Duin was married to another favorite of another count: Henry of Colombier, Steward of  Count Amadeus VIII of Savoy. Colombier was the governor of Piedmont, once served as an envoy to Constantinople, commanded in a couple of battles, and in 1426 served as mediator in peace negotiations between Venice and Milan.

It seems that the old castle, whatever it had been like, was not grand enough for Peter of Colombier. He razed it and built the modern castle over its foundations. The castle is brick, which was the fashion in western Switzerland at the time. It seems to have been largely complete by the time of Colombier's death in 1438. Colombier's castle was stormed and sacked once, in 1530, when the city of Bern conquered the Vaud. The castle had to be repaired and its appearance may have changed, although this is not certain. It changed owners several times until in 1641 it was transferred as dowry to the family de Senarclens, whose descendants still own it. A drawing of 1650 shows that the exterior had its modern appearance by then, although the interior was extensively modernized in the nineteenth century.

Perhaps this is very bourgeois and American of me, but I am still simply flabbergasted by the notion that this gigantic monument is the property of an old noble family. And what do they do with all the space?