Timboli: They may not be selling the older ones, but aren't the Sony consoles backwards compatible? Pretty sure PS4 is with PS3 at least. So in that case maybe the secondhand market has a good life.
Other than that, ports for PC, if not already been available on PC, seem to always be a chance in the future.
Panaias: Backwards compatibility is lady Microsoft's advantage, each Xbox generation is backwards compatible with previous ones. On the Sony side, I only remember the PS2 playing PS1 games. The PS4 definitely does not play PS3 games.
PS3 games seem to have few chances on preservation due to the console's architecture. That changed with PS4, which has a x86-64 based CPU, so it should be much easier to either preserve (and emulate) games written for this console.
To answer the above there is a reasonable ps3 emulator around, obviously can’t mention names here. I have tried it and GOW seems to work well on it (and yes, I own two ps3’s and hard copies of all GOW games!).
In terms of “preservation”, there is no such thing in the digital world. Everything is under copyright law which means ownership of a product is forever and can be brought and sold. Hence can never be considered for preservation other than by the rights holder.
If you want to keep playing something into the future, then your best bet is to get a copy you can play without requirements, eg drm, store integration, console lock like PS4, online requirements etc. All the ps3 games I want to keep are on physical. With PS4 I have a few from the store which are tied to the console, but I would t be getting anything not ps exclusive, better to buy pc version and get a crack.
Oh and backwards compatability is not high on anyone’s to do list, far simpler to keep reselling each new console.