Eh, utilities aren't the main showstopper, zoning is. So much land in cities is zoned for 2 to 3 story single family detached homes, and upzoning it after homes are built on that land is hard to do, and its even harder to find a block that is all willing to sell to one developer. Hence why the edges of gullies and ravines become where high density buildings are built, since low density housing is very hard to uproot.

What this causes is more low density urban infill, which is much more destructive. Where one older home was before, 2 cheap as chips 3000sqft concreteboard boxes will be built as cheaply and quickly as possible. Builder errors like forgetting to put eaves on the house will be fixed by nailing an overhang on afterwards, only to leak 4 or 5 years down the line.

If high density development was easier in urban cores, there would be much less incentive to build shoddy detached housing. As it stands there is a ton of pent up demand, and tons of zoning to block development.