What happens if I take $100 in 2017, diversify it in the stock market, walk away for a year...

then sell everything, and repeat this for ten years?

It’s an unrealistic question. Not sure how to diversify $100, your transaction costs to buy/sell stocks will consume all your capital.

If you want to add 3 or 4 zeros onto the end of your capital $100k or $1m, the end result would depend on what you select to deploy your capital. $SPY, $IWM, $QQQ are a popular mix of ETF’s that have their own risk/reward. Each of these ETF’s (exchange traded funds) are > $100, so you couldn’t even afford 1 share of either of those.

Most full-time traders I know who trade their own accounts (not prop firm capital) have $100k - $5m margin accounts, a few have many times that amount. Don’t expect much from your 10-year experiment. Time will tell, the odds are you will have less capital than you started with and probably wasted 10 years.