why wasn't he drawing backgrounds in widescreen and chopping off the left and right sides to make them 4:3, like what they did for TV shows in the era before HDTV? DC was discussing a widescreen conversion for years (I vaguely remember him throwing out the idea on polls or streams in ~2018), so I'm surprised he didn't try to future-proof his work earlier. I know it's water under the bridge now, but I'm curious if he ever addressed it on stream at some point.
I think he actually started drawing wider backgrounds back in 2020, but the answer why he didn't do it before is probably rather simple. Given that you have to balance a background so it works in 4:3 and 16:9 it's quite a bit more work (I still recall DC tinkering with the cemetery background, so it would look good in both versions) and he probably didn't think an update would actually happen, before he convinced himself that he wanted to do it. If you don't think that you'll ever use 16:9, there isn't a need to make an extra effort to create 16:9 assets.
I don't think DC himself was ever really happpy with 4:3, but up to some point I'd say his plan was to finish SS as it is and to do the next project properly. That very much changed in those last years and now SS is supposed to be "as good as it can be".
But as mentioned before, the problem with this tech update actually isn't the art. If he had stuck to his original plan to only add 5 to 8 scenes and to redo the backgrounds, I'm sure he would have finished the necessary art by the end of July/August last year. I guess I'll never understand why they didn't just hire the people they hired now right in the beginning.
I'm not giving DC any money so I don't really care what they do as long as they are working, but these two last years have certainly cost them a lot of good will and money.