You can't really compare taproot with segwit fork so I don't expect this would be the reason for any major price change,
In 2017 was also US election, this year US election proved to me how it affect bitcoin price in uptrend direction. Also there are other factors that resulted to bitcoinnproce increase in 2017. I too do not think segwit activation really have effect on the price, I haven't known much about bitcoin at the time and I am lazy to relate segwit activation to price of bitcoin few days before and after the the activation.
Taproot benefits are mostly related with scripts and multisig setups, and I doubt many people are using this options.
Yes, but also as the transaction input increases with just one, two or very little output, the more the transaction fee will be reduced of compared to even segiwt. It will also helps consolidation, making input consolidation comes with low fee if compared to segwit.