I think the problem with land-value taxes is that objective valuation of raw land value is actually difficult and even arbitrary. If you say a parcel of land is valuable because there's a building on it, you wind-up with just a real estate tax. If you value all land the same, people will just abandon ownership of large parcels, probably with paradoxical results.
Almost automatically, the assessment of just land has to be harder than the assessment of land plus the property that's there. And assessing land for taxes tends to be politically hard. For example, the overall process of real estate taxation in California was politicized into a disastrous mess years ago with proposition 13. Just undo prop 13 would be a simpler matter and even that likely isn't going to happen.
Further consider, the objective land value of a parcel in Mountain View is probably less than the assessed value a lot of homeowners pay their taxes based on. I'd be in favor of measures that force more intensives use of that land but taking on home-owners with vast political influence is going to be a challenge.