Cloud computing providers are betting on small and medium businesses flocking to them. Large number of SME businesses are already using email service provided by cloud computing providers. It appears that this trend is being spread to other services such as File Service, backup service and web application services.
Businesses offloading their intranet and extranet services to the providers would be left with desktops and some minimal servers in their network. I have my own doubts on merits of moving Intranet services to providers, but that discussion belongs to some other topic.
Desktops normally don't provide any services i.e they don't run any servers. May be printers and other networking equipment have some services, but they are limited to internal machines. Hence firewall protection allowing only internal machines is good enough.
Basically, the requirement of server side security function beyond firewall is going to be less in these environments. In addition, many hackers are now moving towards soft targets i.e desktops and applications running on desktops such as browsers, viewers etc..
Many IPS/IDS devices in the market today protect servers better than clients. Due to movement of services to providers and with increase of client side attacks, IDS/IPS vendors must support better client side detection to survive.
IDS/IPS vendors realized this and moving towards this, but not as fast as one would like to see. By Mid-2009, I believe that many IDS/IPS boxes in the market will have sophisticated engines to support client side attack detection and prevention.