[Alex KL-1]

Ah... well noted. Perhaps a little of language issue (for sure, my English are not sooo good), but I believe I hasten too much to write and oversimplified...

For sure, el-cheapo devices will never have these facilities. But anyway, I saw some only accepting wide resolution settings... go figure.

My concern is not about commentaries from you and our friends here; is about the following:
In general, I regret the lack of options for the legacy monitors. It can't be too difficult for programmers, ie. I don't understand the impossibility to zoom an originally 4:3 video on a... 4:3 monitor (results like I said, everyone can try, using every stream or newer Youtube videos). Since it are coded with 720x480 with side bars, and not 640x480 (for older ones). It will have bars at all dimensions, with reduced dimensions, unless one download a plugin to cut the bars and displays as a 640x480 video.
For the 16:9 monitors, are a blessing that displays the content with correct aspect ratio, ie, with side bars.

I concur 100% about the displaying these content in newer wide screens:
I watch old things like eg. Simpsons with side bars when using modern wide screens, preserving the original A/R.

EDITED*