Intel is dropping some low end chipsets, and may leave that market altogeather.This is a bit of a mixed blessing for other manufacturers such as ATI, VIA, SiS and ULI - they all have low end chipsets, but may not have the fab capacity to pick up the slack from Intel's exit as quickly as they would like.
Intel is expected to keep its higher-margin performance chipset manufacturing going at full blast; after all, it makes more per chipset with those devices.
The demise of the 865 and 915 chipsets is no doubt due to shrinking margins, a migration to higher end systems, and the desire to free up fab capacity for more profitable products. It also provides a ready market for other chipset vendors to fill by increasing their capacity; mind you, it is a low margin niche.
This may even lead to a short-term rise in low end Intel motherboard prices, however the availability of very cost effective socket A and 754 AMD motherboards will likely dampen any price increases.