Omitting landmarks seems arbitrary. Yes, they change the rules, but so do a number of kingdom cards and events, such as Baker which makes everyone start with a coin token and Tax with makes every action supply pile start with a debt token. Even Lost City changes the rules since your starting hand could theoretically contain six cards.
Maybe it would be more appropriate to list the fastest kingdom, wherein all cards/events/landmarks are available and you're not allowed to include more than three events/landmarks. The turn 1 win example is pretty hard to beat, except it includes far more actions than most people ever play with.
Of course, the real underlying question is "why?" To call this the fastest "strategy" is implying that this tells you something important about the speed or efficacy of certain Dominion cards in relation to playing the game itself, which these sorts of puzzles generally don't do, since any one missing piece often makes the whole thing fall apart. When deciding on a strategy, you probably shouldn't look at a board and try to figure out if it matches a speed-win puzzle solution. The odds aren't good.
If you're talking about the fastest strategy in terms of the actual game, the puzzles do remind you of one important thing, which is that certain cards provide opportunities for extremely quick three-piling, such as Villa, Rats and Forum, cost reduction, Traveling Fair, etc. Sometimes you can look at a kingdom and realize that the winning score, and total number of turns, could be in single digits.