Sending small amount of BTC nowadays is not viable at all because of the fees. Will LN greatly help solve the current issue of high transaction fees?

Also, why is Segwit not implemented by popular exchanges like Coinbase and some online wallets when it could help lower the transaction fees? I've read that the adoption rate of Segwit is merely 15-18% only and have already fallen low. If ever LN does come, would it be widely accepted or just the same as Segwit?