A hypothetical Datacenter version might have skipped the optical drive, perhaps cutting down on their losses. At launch I doubt they would have had enough spare processors to build them without cutting into their PS3 production capacity.

Additionally many game studios reported difficulty in writing for the PS3's processor compared to the Xbox, which had gone with a processor pretty similar to most PCs at the time. So by the time they had ramped up the capacity to make enough to meet PS3 demand, there were several years of worse/less performant PS3 versions of games developed for multiple platforms, making Sony's console look worse. It would have been a tough sell internally for the PS4 to use a custom processor architecture again, so they opted not to. This must have soured Sony's opinion of the Cell processor overall.