...

You're referring to dosbox games right?

...

You're right. I had to adjust that manually at nearly every DOS game I've bought here on GOG. Can't tell why, it's obviously that games with a 320x200 resolution need this option toggled on to look properly.

It would be wonderful if they could probe the brain of the current player and automatically set the game up to behave per the player's expectations/wishes.

But then we're quite a bit into big brother territory.

(Do realise that we forum users are the vocal minority in most cases, whereas most users likely expect their games to fill the screen rather than pillarboxing them.)

Then you think Warner Brothers should have released classic movies like Casablanca in a stretched widescreen format? ;)

(Btw. there's still a massive pillarboxing with GOG's current setup.)

...

The reason is probably that they would be flooded by complaints about the games having black edges and not being fullscreen.

Here is another one that prefers true aspect ratios + black bars when needed but I will admit a few games can be stretched and still look okay-ish.

...

Stretching a quality image is just ridiculous. Unless it is supported, leave it alone and get over it. Unless playing with a skewered look is really appealing then so be it.

...

Just curious, aren't most GPU options set to "Full Screen" by default (it's like this in NVIDIA control panel and all laptops with integrated Intel graphics that I've come across)?

If so, setting aspect ratio by default to true in DOSBox would change it to the correct 4:3 format, but it would still be stretched to full screen by the GPU for Joe Sixpack. Everybody's happy. "most users" get their full screen, and those who prefer a true image with black bars have their GPU options set to "aspect ratio" anyway.

EDITED for clarification.

EDIT:
Also, most non-DOS games from 1995-2005 come in 4:3 format. If "most users" didn't have GPU options set to Full Screen anyway, they'd be seeing black bars in those games too. Since those games come in 4:3 and we don't hear many complains about them, why not set the older DOS games in this format too?

...