In Dynamic Hedging, Nassim writes... "Almost one century ago, a young French mathematician named Gaston Bachelier had the insight (among other surprising intuitions) to write, in his doctoral thesis, see Bachelier (1900), that the expected price tomorrow of a call value was today's. He gave the right answer to what most option beginners fail to understand: that time decay is not expected P/L from an option. If the option is priced at the right volatility (assuming interest rates are 0), time decay will be expected to be 0." So what is the true P/L from an option if it is not theta?
Your 'question' presupposes a wrong-headed premise: that theta does not belong being listed with the primary factors of an option's value. BSM gave us time, distance, rate-of-interest, and volatility. • Rho? Nobody talks about, as changes (since the 70s) have taken place outside of option life cycles. (Real Option studies are wonderful, though...) • Theta? You claim it a no-go. That leaves, • Delta and • "Vega"... Since you know all this, I am left wondering what your real question is.
All your answers so far has been to a question I never asked. Never said theta isn’t involved in option value, and never said theta isn’t a fact. Theta isn’t the source of a options P/L for trader. CAPEESH?