Debian drops mainframe, Sparc development

It should be more like "Some Debian developers suggested that maybe some architectures should not be supported in the next 'stable' release of Debian."

Can someone enlighten me why IA86 is proposed being supported?

There is roughly 50K itanium servers in the world based on IDC numbers from 2004 / 2004.

80% is from HP that uses mostly OpenVMS, on the Linux front they support RH and Novell/ Suse. IBM sold a few Itaniums and Linux on those is same as HP. Finally SGI Altrix but as far as I know they use their own distribution tailored to the super computer market.

This leaves what for Debian. 2%-3% at best equal to somewhere around one to two thousand machines. Why is this proposed supported over Sparc or Arm?

Makes little sense unless HP pays Debian directly, and dropping Itanium would be seen as the last blow for Itanium so Debian can pretty much name any price.

HP is going full tilt Itanium and will officially EOL their PA-RISC processor this year.

Mistake? Probably. But HP set their engine in motion back in the mid-nineties and nobody at HP seems to know how to stop the train. By the way, that same "engine" included elimination of all HP operating systems and moving exclusively to Windows NT (the next gen version of it at the time). That was back when M$ was actively trying to port NT to different architectures.