If that "certain timespan" was the eighties then what you are seeing is more that they used the exact same colors... which were designed to be seen on yellowish

If that "certain timespan" was the eighties then what you are seeing is more that they used the exact same colors... which were designed to be seen on yellowish newsprint that sucked in a ton of ink, instead of bright white glossy paper that all the ink sits right on top of. Over time people mostly quit doing that. Once it became reasonably easy and affordable to deal with a multi-layer 300dpi (or better, it's always nice to be able to have your minor mistakes vanish when it's shrunk to print size) file, and for that file to get turned into four CMYK plates, comics colors started to look a lot better than when everything had to be planned in watercolors over a xerox, then turned into those four CMYK plates by hand.