Idk, I’ve seen plenty of houses get torn down and replaced by a $2M house and just sit vacant years until they sell.

15k/2M is 75 basis points. Its definitely profitable to just sit on land especially if you turned it into a parking lot or some other barely improved thing.

On a 2M house the current property tax burden in california is $20,000 a year. More if you have Mello-Roos taxes in that subdivision.