Tourbillon is a complex piece of machine. It's a complication that is much more difficult to design and manufacture than a "regular" movement. And nowadays its just a showcase of manufacture capability for a watch manufacturer. The rarity and prestige of a well made example demands a high ticket price, you do have to pay to play. Beware that not all swiss watch manufacturer that sells a watch model with a tourbillon movement manufacture their own owner, some are "out sourced".
Not all tourbillon has a 6-figure price tag, there are numbers of China made tourbillon watches that sells well under $1000. They are widely available on Amazon and eBay. I think those are great fun to have and you don't have to put your house up for sell in order to own a tourbillon ... LOL