It's not that simple. There's a limit to downgrading games, much like Arkham City failed to make to the Wii. 

Also, notice that in your PC example, there is a hard limit that are the minimun specs. Try to run Just Cause 3 on a GTX 550.

That's what it mostly comes down to, yeah. With enough time, money, and rapid determination you could probably get just about any PS4/X1 game to run on even a PS1. The more technically complex the game though, the more of each you will need. I was just pointing out that on the effort list, i'd say RE7 is lower than average for a major recent release.

Well, it probably won't happen this year. Overall I think it is possible, I would say 50:50 depending on some circumstances.

First: technical reasons aren't preventing a port. 3D-games can scale a lot, dropping resolution, frame rate, effects, polygon detail, texture detail etc. does a lot. I doesn't look so well, but still works. You see this with games on PC, you have there a lot of technical options that can make the game look better and more resource-hungry or looking worse and less resource-hungry. This adresses a big range of machines.

The main reason for Capcom to decide over this are sales. This is tricky. Nintendo platforms usually have worse sales for grittier games. But it has a history of some horror games, and specifically Resident Evil. See RE4 on Gamecube, Umbrella Chronicles on Wii or Revelations on 3DS. So, Capcom might be willing to try again. Skyrim might give Capcom (and other third-parties) a good indication if the audience of the switch is willing to buy stuff besides Nintendo-games. So, if Skyrim runs well, it might increase the chances of RE7 or RE8.

There actually was smaller dev that pitched an Arkham port for Wii. They developed a small demo to pitch the project. Considering the downgrade in hardware, it didn't look to bad.

Of course. the Wii was a more dramatic case. But we also had a lot of current gen games that had their PS360 version cancelled due to not handling the game anymore (MKX, per instance). The Switch isn't exactly a powerhouse, so a lot of stuff can't be ported without huge reworking. A lot of current game engines are built with material-based renderingand other tech that make them quite hard to downscale.

Your Just Cause 3 video shows the game dipping all the time in the low 20s. Would you say it is playable?

About as much as a Red Dead Redemption 2 Switch version.

I'd say near zero.

They are porting the engine, so I can see it coming eventually.

I wouldn't say 0. The game has underperformed on PS4/XB1/PC (per Capcom's expectations). As such Capcom could possibly be keen to get it on Switch to eek out a few more sales. I'm not sure about how much work that would require though and whether or not they believe that it's worth it.

I'd say the odds are 40% yes-60% no. Fact is we really haven't yet seen any "big scope" PS4/XB1 release get announced for Switch.

About 3.2%...