Don't underestimate the advantages of a diversified indexed approach. For example:
1. You are guaranteed to earn the market rate of return every single year.
2. It takes a few hours to set up, and about 1-2 hours a year to maintain.
3. Most years it outperforms cash, and in the long-run it massively outperforms cash.
4. If the portfolio is well-diversified, losses even in terrible years are manageable. E.g. the normal portfolio in 2008 would have lost about half what the overall market did, and would have been back into positive territory by 2010. The conservative portfolio would have lost only moderate amounts in 2008, the worst market for 75 years.
5. It is tax-efficient, and dealing costs are low.
Now consider the disadvantages of an active portfolio.
1. You have huge risk of underperforming the market, or even suffering large outright losses.
2. It takes a huge amount of time and effort, and a certain level of natural ability, to get to a level where you can hope to regularly outperform.
3. Your taxes and dealing costs are high.
4. The odds are that you will underperform the market.
5. A portfolio of 100% stocks (or shifting from 100% cash to 100% stocks via market timing) is far, far more risky than one that is split between stocks, bonds, real-estate, and gold.
6. To successfully time the market requires several difficult decisions to be made correctly: i) getting out at the right time ii) staying out until the bear market is over iii) getting back in at the right time iv) staying in until the bull market is over v) riding out the various corrections vi) selling again at the right time once the bull ends. The odds of getting all of those right, every market cycle, for years on end, are incredibly low for the average trader or investor. The net result is usually what our thread-starter has experienced - getting out, and then staying in cash for 5 years, and who knows how many more years he will stay in cash for. Meanwhile, each year corporations earn net profits and thus increase their net asset value, bonds throw off coupons, and REITs throw off generous cash yields.
Staying in cash does not reduce risk, it increases it. The risk comes in the form of failing to keep up with inflation over the long-term. This can be a far more costly mistake than suffering a 20-30% drawdown once every 10-20 years, which in each case is recovered within a year or two, occasionally 3-5 years in the case of a 1929-32 scenario. Far more money has been lost by sitting in cash earning a pittance for decades, than has been lost by participating in the economic returns earned by investment assets over the long-run, and in the vast majority of calendar years.