So, why isn't any major hosting provider offering a multi-tenant Linux container hosting service directly on bare-metal Linux servers, whereas Joyent is providi

So, why isn't any major hosting provider offering a multi-tenant Linux container hosting service directly on bare-metal Linux servers, whereas Joyent is providing Docker-compatible container hosting on SmartOS using LX-branded zones? Does anyone trust the security of Linux namespaces and cgroups in a multi-tenant environment? That's the one thing that SmartOS really seems to have going for it.