That's a question that I ask myself too.
As getting older I hesitate more and more to carry 10-12 kg backpacks, at a certain point I will have to sell some of my equipment and buys something light. But here comes the "zoom" issue. There isn't any good universal lens so I guess I'll end with some full frame mirrorless and two lenses or I will finally surrender and travel with a phone only. :)

!DHEDGE