"Cash drag" and "inflation" aren't good arguments in favor of blindly investing for the sake of investing when your timeframe for deploying capital is within a 3 year period. This "cash drag" thing is repeated ad nauseum on reddit to anyone expressing doubt about buying stocks or expressing interest in selling stocks that they own (funnily enough, except for in Wallstreetbets.)
Despite M2 expanding by 3900% since the 1970s, S&P has dropped by more than 30% 12 times. Inflation did not pause or reverse when any of those happened. Stocks can and will drop 30, 40, 50, 60, 70% during red hot inflation. You aren't compensated by this loss with deflation, you lost in both directions.
If our economy is so different since 1970 (which it absolutely is), why did 3 of these 12 events happen in the past 25 years?
If we're not Japan, why did we have two lost decade episodes since 1970 where stocks were flat and real returns negative for 9 years? Inflation raged on during these, it didn't get put on hold just because your stocks went nowhere (after they crashed first).
If real returns have supposedly been parabolic since ZIRP was implemented, and the S&P is a "guaranteed 10% per year" why does the S&P to gold ratio show that the S&P has actually declined relative to gold since 1962? Gold is a terrible investment, but this does not say nothing about our economy.
When I see people saying Warren Buffett should have used some of his cash to bought S&P 500 index funds or shares of semiconductor stocks because his "cash was dragging" and "inflation was eating him alive" I just have to wonder if any of them have any risk management protocols for their money at all. I'm not saying emulate Buffett or take him seriously.
"Don't time the market, DCA into an S&P 500 index fund" is actively engaging in market timing. You are choosing to buy at the current price, and you are NOT choosing to NOT buy. You'll have to "time the market" every single year of your retirement with the 4% rule if you believe in it, too.
Blindly saying "S&P500 index fund" or "buy the stock now or your cash drags" isn't always the correct 1 size fits all advice, and sometimes it's simply incorrect advice in the context of macroeconomic factors.