i was gonna say that, but if the developer wishes to make a technically more impressive game then the best of ps3, the hardware is easily more thn capable.
Honestly, there's already games on Switch better than anything on PS3 graphically; TLOU may be a great feat of technical engineering and art design, but ultimately its running on less than 500MB of RAM and a GPU from 2006, so it is not technically demanding.
What you have stated is accurate but its important to also state that in portable mode the Switch graphics resources are much reduced often rendering at a sub HD resolution to maintain frame rate which is worse than 360 and PS3 resolutions, I know that isn't the full story because of the later architecture of the nvidia gpu and an improved feature set and more efficient design but still it is clearly struggling when in portable mode to maintain 720p.
Also again I have to point out storage limitations of a mobile system. PS3 had games on dual layer blu-ray discs giving 50GB of storage on cheap optical discs plus could store large patches and updates on its hard drive. This design gives it more space for the actual game even if its main memory is less. You are never going to get the very high quality 7.1 soundtracks on Switch that the ps3 had on many games and huge variation in realistic textures.
I seem to remember one of the uncharted games was a 50GB download so that definitely maxed out a dual layer blu-ray disc.
I'm just pointing out there are other factors. Rayman Legends on Switch has slowdown and compression artifacts in some visuals purely because they have made it as small as possible but ended up making it inferior to ps3, 360 and wii u purely because of heavy compression and aiming for a small file size.
LA Noire is only slightly smaller file size than PS3 on Switch at about 28GB but on a PS3 that easily fits on an optical disc or as a small chunk of its hard drive capacity but that way exceeds the free space available on a Nintendo Switch's flash memory. I haven't looked at LA Noire sales on Switch but you wonder how it can sell well when it is limited to digital sales only to people who have bought large capacity micro sd cards or a cartridge game that still requires a 14GB download due to its 16GB rom size. 14GB is still a huge chunk of what is left over from its standard 32GB memory.
I only mention this as most games have not gone the LA Noire path but instead made the effort to reduce the size of the game. Lets also not forget the ps3 was absolutely brilliant at compressing itself, the cell was pretty amazing at doing background compressing and uncompressing on the fly which probably helped with the rubbish 256MB x 2 memory system. There is probably a 3x CPU advantage of the PS3 compared to Switch when you factor in the cell processors although developers who could max out ps3 cell performance are probably in the minority. Even the 360 with its DVD drive still had large hard drive capacity although some larger games were delivered on multiple optical discs.
So yes the Switch has a more powerful GPU and much larger main memory but there are other factors in play when you consider the downclock in gpu performance for portable mode and lack of storage capacity.
PS3 had some amazing pre-rendered 1080p movie sequences in games with amazing 7.1 soundtracks. They can add a lot of atmosphere and add to the story telling.
The point is some types of games will remain superior on PS3 mainly due to storage and CPU performance where as others probably the majority will clearly be superior on Switch and many will have attributes that vary between them on which is superior. I feel it unlikely the Switch will ever match the PS3 for audio quality and game soundtracks.
LA Noire is definitely a game superior on PS3 and 360 I would say despite the huge file size on Switch.