And you know this because you can run a bead with a Miller wire feed MIG?

I can assure you I have worked with a number of different metals and
joining systems. I also understand at least the rudiments of metallurgy,
and in particular how it applies to bike frames and components. I
can probably still put shoes on a horse, but it's been some years,
and alloy shoes don't last very long.

I believe you genuinely misunderstand the welding process, the effects
it has on the areas adjacent to the weld, and the heat treating process
in the case of thin wall aluminum tubes. You also seem to lack some
appreciation of the stresses involved in the area in question. I don't
think you intentionally mean to hurt anyone, but the road to hell is paved ........................