That's exactly what it was. That's why, in his DMG, Gygax complains about GM's who allow their players to get the high score without having to try hard.And here I was thinking it was a high-score mechanic akin trying to get your initials in the top slot of a Gauntlet arcade machine. How much gold could you acquire before GAME OVER.
"Trying hard" in this context is where the skilled/smart play comes in. I agree with @Willie the Duck that in this context we're not talking about rocket science. But it's clear from how Gygax describes play in his PHB and DMG, and also from Moldvay's advice to GMs in his Basic rules, that their basic conception of play was of players who will explore the dungeon, exploit their fictional positioning in doing so, and need both a bit of that skill and a bit of luck to grab the gold. That's why such a premium is placed on GM's coming up with new monsters, new traps, new "tricks", etc - these are the analogue of adding new levels and/or new special features to the Gauntlet machine.
My view - a conjecture, rather than an empirically confirmed fact - is that D&D became popular in the late 70s and early 80s despite, and not because of, this assumed default playstyle. I think players liked pretending to be someone else, and enjoyed the heroic fantasy aspect, more than they really wanted to participate in the gameplay ecology of poking and prodding statutes, escalating through ear seekers and wire-netted ear trumpets, etc. Hence why 2nd ed AD&D veered pretty sharply away from the default assumption and there's been no return to it since by WotC. (And while the OSR is fairly vocal, I doubt that in numerical terms it is more than a fraction of the number of players using 5e D&D to play in the post-DL/2nd ed AD&D style.)