Sony makes a loss on the sale of each PS3 console, but earns a lot of revenue from the sales of games released for the platform. The use of dozens of PS3 consoles in research labs for raw computing power or a similar task, would be seen as hurting Sony since no games are bought for any of those consoles. In the past this reality has even caused some speculation that a Sony update would kill, or limit, the OtherOS feature on older consoles.
However, SCE has committed to continue to support the OtherOS feature on older models. A sony rep gave the reason for the lack of OtherOS support in the new PS3 Slim on a Sony developer website...
"The reasons are simple: The PS3 Slim is a major cost reduction involving many changes to hardware components in the PS3 design. In order to offer the OtherOS install, SCE would need to continue to maintain the OtherOS hypervisor drivers for any significant hardware changes - this costs SCE. One of our key objectives with the new model is to pass on cost savings to the consumer with a lower retail price. Unfortunately in this case the cost of OtherOS install did not fit with the wider objective to offer a lower cost PS3."