IP4 address conservation method

[swmike at swm.pp.se (Mikael Abrahamsson)]

I read:

http://www.nanog.org/sites/default/files/tues.general.Papandreou.conservation.24.pdf

I would like to point out RFC 3069. On most cisco equipment this is done 
using static routes and "ip unnumbered".

So my question is basically: What am I missing? Why can't data center guys 
not build their network the same way regular ETTH is done? Either one vlan 
per customer and sharing the IPv4 subnet between several vlans, or having 
several customers in the same vlan but use antispoofing etc (IETF SAVI-wg 
functionality) to handle the security stuff?

One vlan per customer also works very well with IPv6.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se