Thank you for taking the time to explain in BAB, one trades long/short.That's not how it works. For a factor loading, you need to be long-short. In this case short high beta and long low beta and adjust for leverage.
Most of the ETF's give half the loading (since long only). For argument sake, take your argument high beta out-performed in the up market. There is high beta ETF called SPHB. We can pretty much agree that we are in upmarket since 2012.
Here are the results. Portfolio 1 is SPHB and Portfolio 2 is levered SPY. I adjusted the leverage, so that both of them have same standard deviation. SPY portfolio is almost twice bigger than SPHB
View attachment 197592
On second thought, looking at your example, in an up trending market levered SPY outperforms BAB SPY in almost all aspects of measurements.
Isn't that similar to what I said: a simple BWB is better than BAB?