Your argument is based on a mere subjective preference for actions and cards
That subjective preference is based on thousands upon thousands games of observing how I win the game and how my opponents win the game. It's not even a particularly radical notion.
No idea about how you perceive any validity in that claim. Decks that draw themselves don't occur so rarely and in such decks you prefer a double Peddler over a VillageLab. Not that this is the only situation in which Peddler˛ is superior to Lost City. If you can trash most of your starting hand you will do better with cantrip payload than with LostCity draw and Gold payload.
The cards are simply of similar strength. Otherwise Kingdoms in which Grand Market is present wouldn't be virtually always focused on GM (sure, the extra buy isn't trivial). You might wanna explain how this situation arises if Village&Lab really were "worlds better" than GM without the extra buy.
How do you ever get to the point of having a deck that draws itself if you don't have draw and actions? Sure, Peddlers are pretty convenient in that deck once you've built it, but being able to have that deck in the first place is the important part, and Peddlers don't enable that.
Saying that you'll do better with X than with Lost City draw and Gold payload is like saying that you'll do better with X than with Scout in a deck with no Victory cards. If you have Lost Cities, either you should also be having terminal draw, or your payload should be terminal, both of which are a significant improvement over just having cantrip payload in a thin deck. Of course the +actions you get from Lost City aren't that impressive if you never play any terminal Actions.
And no, the cards are not simply of similar strength. Kingdoms where Grand Market is present aren't virtually always focused on GM, and when they are, it's usually because there's also some actions and draw present.