Lighting network defiantly seems like a viable solution. The other way I'd look at this is Bitcoin is great for big purchases - houses, cars, etc
That's not enough, the main thing is volatility we have numerous ways to make the transaction of bitcoin faster but the volatility is passive in bitcoin and they are right if you really want to make Bitcoin as a reliable way for payments most especially for microtransactions then it needs to be stable like the other stable coins and fiat did, big purchases are also fine as long as you are planning to hold bitcoin.