It depends on what kind of flats you are getting. A daily commuter in Colorado i had been getting goat head thorn punctures at the rate of 2 to three a month. Since I began using tire liners 20 years ago it is now more like 1 to 2 a year. I've tried more robust tires, and summer very grippy, but they are not supple. They have been a judge to ride Tire liners allow me to use soft sidewald tires and have that extra puncture protection.

I will say that the tire liners are not a panacea. Glass shards, Metal slippers and other road debris can work their way into the tire and eventually through or around the tire liner. But for my type of writing that is rare. I have had Machine screws and refers nails go right through my tire, And I don't know if a more robust tire would have stopped that.

The question is what do you hope to achieve and what are you willing to sacrifice to achieve it. For my type of commuting in my area I have been very happy with tire liners in supple tires.