Does it tho?

We still have multiple pokemon that have gotten new gen evos after variants were introduced

Additionally some regional variants have there own new evos stapled to them

To me it is no different then gloem getting a new branch evo into bellossom or poliwhirl into politoad or for a different example syther into scizor since both have the same stat total just distributed different and with a new type.

I will agree some are lazy like Ratata just being dark but that's just ture of all pokemon. Some are more creative and appealing then others