If one can foresee S&P500 delivering 0% return over next 2 decades, would it be beneficial to invest in dividend plays instead?

Dividends and growth are never guaranteed

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among the S&P500 stocks there are very many that pay dividends

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4% is nice

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there are no prophets

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Depends on your stratergy. We can never know, remember to focus long term and not invest for the short term. Also, note that there are always people who are negative and bearish on the markets, if you want to find someone to quote, you can certainly find more than just a hand few every year. This isn't the first time yet people will always say "This time is different." Look long term if you are investing.

If you are trading, you can profit in any direction.

Dividends are not guranteed, it depends on the business revenue and performance. Dividends can be cut as evident this year.​​​