Yes, the average Joe can take advantage of a bear market (not crash) and profit from it. Note that a crash and a bear market are different beasts. 1929 and 1987 were crashes. Unless you had some form of negative correlation protection in place prior to them, you paid the piper. Bear markets like 2000 and 2008 took 18 months to unfold so they offered lots of time to react and adjust.
There are different approaches to protecting profits, reducing your losses, or profiting in a bear market.
Buy & hold types recommend diversification and reallocation. That's just a way to spread the losses across various sectors, hoping that some positions don't lose as much as others. But you will lose. You take the beating and ride it out. Be aware that a drop of 50% (see 2000 and 2008) requires a 100% recovery to break even (ignoring dividends).
Some recommend gold. Sometimes gold correlates, sometimes it does not. It's iffy.
Some recommend stop loss orders. That's fine in a correction but in a crash, you have no clue where the fill will be if price gaps through your stop loss price.
You could write covered calls but that provides limited downside protection and if your stocks crater, you won't be able to continue doing so without locking in a loss.
You could buy puts but doing so has several issues. At the current level of implied volatility, at-the-money portfolio hedging with SPY puts costs about 8 pct a year. Puts on individual stocks tend to cost more. That's a lot of portfolio drag to overcome if the market stagnates or moves up modestly. You can reduce put protection cost if you use OTM puts but that adds a 'deductible' to the equation (loss from current price down to the put's strike price). If you buy protective puts and the market moves up, additional gains will not be protected.
If you are comfortable with giving away much of the upside potential gain, you can reduce/eliminate put cost by collaring long stock. Sell OTM covered calls to fund the cost of the protective puts. Collared long stock is synthetically equivalent to a bullish vertical spread and has a defined and limited R/R profile. With some luck and cooperation by the underlying to the upside, you might be able to continuuosly roll the collars up, protecting additional gains.
Other approaches to hedging/profiting include:
1) Buy inverse ETFs
2) Run a long/short portfolio
3) Short stocks, ETFs, futures
Transitioning to cash or quality debt is something that any investor can manage. Managing the downside requires more experience and effort. Add a small portion of negative correlation positions. Transition to more short as the market drops further. Let your portfolio’s declining value dictate the transition from long to short (and vice versa). React, don't predict.