it is not about size of the miners, the small ones can stay too. in fact it is more possible for smaller miners to stay even if price goes down. for example if you are a hobby miner who believes in the future of bitcoin and are mining with 1 ASIC at home you usually don't even sell the coins you earn and hold them as an investment.
It depends. People are very easy tricked into believing that they will hold no matter what, but when the price goes down people start stressing out, and when bills pile up the far majority of these smaller miners will choose to liquidate some of their earnings to not end up in red numbers. Only the most hardcore hobby miners will have the patience and dedication to keep holding through a bear market, but there is a limit to all of it.
if a miner (big or small) is somewhere with cheaper electricity they will remain active even when price falls.
Cheaper electricity isn't always the leading factor. Large miners even with higher electricity rates can still be more profitable than those with lower electricity rates. One of the most important factors is how frequent a miner generates its blocks, and in case of Bitmain's pools, their operational costs are far under $5000 per coin.