Ze kanjoos abrahamics, aka the jooz...already do this. At least in Canada. I've seen two jewish cemetaries in Canada - one in Vancouver, one in Toronto - both are vertical silo mode graves. They are ironically, also the older of the cemetaries, approaching close to max capacity: a jewish friend of mine told me that the modern jews prefer the isloo-christian way of horizontal burial over vertical burial, which became vogue with joos in the late 1800s as they were being pogrommed outta Europe and arriving in americas in record numbers and taking up as less land as they could.
This is because when u bury vertically, the gravestones are a lot closer together than when buried horizontally and apparently grieving families who pay homage to these tombstones have less privacy from fellow grievers in the vertical arrangement.