Both normal and spoilt, I think.
We've just had that with DCs on a long-haul holiday, admittedly not as "exciting" as it's "only" to my home country which we visit regularly, but we always stay in nice hotels and do several locations to provide interest and variety. And all the locations/hotels/activities are always chosen with full family input, so nothing is pressed upon anyone.
Yet DC did lots of sullen flopping on chairs tapping away on phones, often minimal conversation with us and my elderly parents/relatives who so rarely get to see us. And pulling them up on it just seemed to cause more resentment and sullen behaviour.
We spent some of the holiday in a gorgeous beach/nature resort. One morning DC asked to be woken up early to come for a dawn walk on the beach - then when we did as they asked, got shouted at and they took so long dragging themselves out of bed that we entirely missed the dawn. The resort offered free morning/evening nature walks, DC refused to participate, preferring to sit in the hotel room with their phones. Dragged their feet about going in the pool or sea, because "who's going to guard the phones if we're all swimming?" DH and I just shrugged our shoulders and went on all the nature walks, had dawn beach strolls, night-time stargazing as a couple etc.
I said to DH that I'm a bit torn, my parents are too frail to travel so if we don't travel there, they'll never get to see their grandkids. But equally, I'm not best pleased about spending £££££ to have a pair of sulky screen-addicted grumps who could be sitting at a bus stop at the end of our road, for all the difference it makes. And I very much enjoyed the grown-up couple time, TBH. We're quite seriously thinking about making our next trip a two-person one.