Would fees go down once more people start using segwit addresses for day to day activity? Since the fees are high today, when more wallets and people start using segwit (bc1) addresses. Would sending from legacy address fees go down as everyone is using the newer address? Or it doesnt matter?
Transactions which spend from segwit outputs (i.e. "send from" segwit addresses) will have less weight (as in block weight) than transactions which spend from non-segwit outputs. This means that to reach the block weight limit, blocks will need to include more transactions. This effectively means that there will be more block space for more transactions. Since more transactions can be included per block, the transaction fees in general will decrease.

So yes, when segwit is widely deployed and if it is used in all transactions, the transaction fees will likely be lower.