A small part of it might be lack of confidence, however, in my opinion it's the incentives that matter the most, I only have to pay a few cents for an on-chain transaction and I don't mind waiting for a few minutes for this to happen, why would I bother with using lightning network or any off-chain technology? if mass adoption becomes a thing, and the network gets congested, and as a result I have to pay say 5$ to send 50$ then I will have to use lightning network or any other reliable second layer solution, and the same thing applies for when bitcoin becomes a poplular means of payment for everyday's items such as grocery.

LN is built for the future IMO, it keeps bitcoin a couple steps ahead of time, and if we get more people to start using bitcoin, we will have something that has been tested and worked perfectly for a couple of years.

If you are interested in trying LN, bluewallet is a nice mobile wallet for both Android and IOS, you can also use it along with sat2.io to send bitcoin by phone number.(credit goes to omega for pointing this out in our local board).