Apple did the same again with their ARM migration and in my experience it worked great. I believe Microsoft also has a solution for running x86 software on ARM.
The original Rosetta, which was emulating PPC on x86 is directly comparable to the situation of PS3-game-on-PS4 hardware. I was able to play Halo CE for Mac on x86 with Rosetta and it felt native.
The point is that this isn't a limitation of technology, this was a decision on Sony's part.
Apple did the same again with their ARM migration and in my experience it worked great. I believe Microsoft also has a solution for running x86 software on ARM.
But Apple’s solution isn’t pure software emulation, the SoC has special hardware inside to make it translate a lot faster.
The original Rosetta, which was emulating PPC on x86 is directly comparable to the situation of PS3-game-on-PS4 hardware. I was able to play Halo CE for Mac on x86 with Rosetta and it felt native.
The point is that this isn't a limitation of technology, this was a decision on Sony's part.