Thank you for the in depth response, greatly appreciated and insightful
You're welcome. The TLDR version is that both NTSC and PAL had pros and cons but the PAL cons are easily fixable in an emuator if they put some minimal effort.
How difficult is it to implement these fixes that makes PAL versions run at 60fps and at the full screen size? And does it come with any downsides? i.e bad frame pacing, pixel crawl, etc
Can this be done in Retroarch?
I’ve used emulators a lot but unfortunately I have zero experience in this.
Some emulators have an option in its settings to force 60hz for PAL games. I assume internally it simply "overclocks" the emulation or display to update 60 times per second instead of 50.
So for games that were slower in PAL compared to their original NTSC version (typical from games made in Japan or USA and had a bad PAL conversion) this patch would fix it.
For games that are properly programmed to work at the same speed indpendently of the refresh rate or resolution (but moving smoother at 60hz than in 50hz) to apply this patch would mean the PAL game would run as smooth as the NTSC one.
I don't know if there is some case but there is a possibility of a another type of bad implementation: an European game designed to run well at the speed of the 50Hz but not designed to adapt to other framerates or refresh rates. In this case to have the 60Hz patch activated would show all -or maybe some- things running faster than usual which probably could even break the game. For these games the patch should be disabled. Not only to keep an optimal experience, but also to keep the intended one.
Retroach isn't a single emulator: it's let's say a collection of different emulators (cores). To change its options, it has two level of settings: one from retroarch that are common to all cores and are applied to all cores. And then core specific settings, that only apply to that specific core and are different for each core. Some cores (can't remember which ones) of old home consoles have this core specific option to force 60Hz. When saving the core specific settings, as I remember you can save it for the core, only for a roms folder or only for a specific game.
Regarging the letterbox black bars in the top and bottom of the screen of some PAL games: some retroarch cores have core specific options to "hide" (or not render) more or less portion of the top and bottom. So playing with this setting you can fix it. Retroarch also has in the retroarch level settings video optioins to zoom and stretch the image in many ways, automatically adapt it to different aspect ratios etc. So stretching the image vertically enough to keep the black bars outside the screen for that game would fix it and look like the ntsc version. The PS5 emulator also has stretching and zoom options so they could solve the black bars letterbox issue too.
Both the letterbox and 60Hz patch would be needed for some PAL games but not for other ones. Which means that before releasing each PS1 game they should test to know if each game needs to have them activated or not. Or well, even if they want save money on testing they could simply add them to the emulator settings and let the players decide if want to activate it or not with the warning that it can make the game look bad or even break it.
Please notice these aren't a PS1 specific issues. It applies to all home consoles designed to run on CRT tvs and their retroarch cores, so from the PS3 gen to back to 8 bits released both in Europe and America/Japan and from devs from both sides. So basically everything from NES to PS3.
There were also other differences between PAL and NTSC or with the different cables you were using to connect them to the tv that resulting in having more or less blurriness or artifacts, or more importantly a slightly different color palette. Some retroarch cores/emulators also have options to change between them, or there are retroarch shaders (let's call them visual filters) to simulate each one. But well, most people don't care about them.
If all this NTSC and PAL are such an issue then just release the suitable version for each region.
Game makers have been able to figure out how to release physical copies in their own cover art and language. How hard can it be to give gamers downloadable copies that fit their region?
When they use the same version for the whole world is to cut costs from testing: in the case of Sony when you submitted a game to be published, you sent each version to the different Sony teams for each countries/regions. Each one had a different testing and certification team an required to verify different things.
By having a single version reduces the amount of bugs and testing and certification required.