Sony didn't create the cell architecture to prevent efficient emulation. At the time, manufacturers tried to get as much performance as possible from the manufacturing dollar under the assumption that developers would optimize their games for the machine. It was actually a partial failure, as few third party titles made full use of the architecture.
Kinda, in so many respects the PS3 SPU's that many hated was just taking the PS2 VU's to the next level as the programming model was very similar(shuffle blocks of data via DMA to fast vector units).
As a former PS2 developer I mostly thought "cool, VU's with more memory".
Few games really utilized the PS2 to it's fullest either (there's an port of GTA3 and GTA:VC to the older Dreamcast that's coming along very well).
The thing that really bit Sony here for the PS3 was that many PS2 titles (The PS2 GTA games being the prime example!) used the Renderware engine (a few others were available but it was the most popular afaik), so the complexity of the PS2 never really hit developers who were making games just below the absolute top tier.
When EA bought up Renderware slightly before the PS3 release, they closed off sales while honoring existing sales only so the most used cross platform engine was suddenly off limits to most third parties for the PS3 (Iirc is why Rockstar released that ping-pong game as an engine test before GTA4 and 5).
And the perceptions about third party engines also took a hit so not only was the most popular engine closed off, bigger developers were also became wary of relying on third party engines at all (during the PS3 period) until Unity later took off from indie usage.
