Lager, when the PS1 was a bigger hit than anyone thought it would be, most publishers were in a frantic, headlong, ill-considered rush to get onto PS2 when it launched. It was bizarre; it was so easy to see for anyone with two or more firing synapses (note: this definitively excludes sales/marketers in the game industry) that money was being LEFT ON THE TABLE with the huge install-base of PS1 users.
For some reason, everyone wanted to abandon PS1, and rush to the smaller installed base. It's made even more crazy when we look at how much brand new dev kits cost at the outset of a generation, and how many publishers walk away from the big investment they already have in knowledge, pipeline, etc. in the older hardware.
Apparently people learned their lesson, because this didn't happen with the transition from PS2 to PS3, and it isn't happening as we transition to PS4.