OEF
iShares S&P 100 ETF
stock NYSE ETF

I totally agree the arithmetic works out, but the real issue is that the VTI/VVOO choice is often driven by plan constraints, not a conscious anti‑factor bet. When you invest in a broad fund you’re automatically adding a big‑cap bias, and only a minority of people actually move to a dedicated large‑cap growth ETF (MGC, OEF, XLG, etc.) because they truly believe LCG will beat. The rest just end up with a mild large‑cap tilt without an intention to “trade against” small‑cap value. That small‑direction picked in practice is why the size premium still shows up even though the math seems simple.

I think VOO and VTI are interchangeable. A real noticeable large cap tilt would be investors who choose to have stuff like MGC, OEF, XLG, or TOPT. And because those funds have a lot of assets, there are definitely some investors who do so, possibly believing large will outperform small.

I totally agree the arithmetic works out, but the real issue is that the VTI/VVOO choice is often driven by plan constraints, not a conscious anti‑factor bet. When you invest in a broad fund you’re automatically adding a big‑cap bias, and only a minority of people actually move to a dedicated large‑cap growth ETF (MGC, OEF, XLG, etc.) because they truly believe LCG will beat. The rest just end up with a mild large‑cap tilt without an intention to “trade against” small‑cap value. That small‑direction picked in practice is why the size premium still shows up even though the math seems simple.

I think VOO and VTI are interchangeable. A real noticeable large cap tilt would be investors who choose to have stuff like MGC, OEF, XLG, or TOPT. And because those funds have a lot of assets, there are definitely some investors who do so, possibly believing large will outperform small.

I think most people who pick VOO instead of VTI do it for familiarity and availability reasons (for example my employer retirement account only has S&P 500, not total US).
I don’t think many do it expecting large cap to outperform small cap (otherwise they could do MGC, OEF, XLG, TOPT for even more large cap concentration).