I don't think it's only single parents. I am also a bit
at the "just take a romantic break" notion.
DH and I have no parents and live in another country to our DB's who lived miles away anyway when we were in the UK, and would never offer childcare. DH was in the army so I would often spend weeks and weekends alone and working full time.
We've had a handful of nights out in 9 years thanks to a babysitting company, and a nanny on one of these resorts people are chastising.
We also like to visit destinations that get quite warm, and for part of the day it was always good to have the option of some crafts or activities in a cool place out of the sun for DS when he was younger. So he would have lunch and perhaps go and make pizzas, learn to Calypso, decorate a tee shirt until it got a little cooler, then he could join us and enjoy a splash in the sea/pool or time on the playground.
I'm not sure of the resorts others are looking at, but the ones I've stayed in at St Lucia, Barbados, Maldives etc had menu restaurants so if wasn't all buffets, trained Nannies and if there was any evening entertainment it was usually calypso bands, hog roast dinner on the beach etc hardly bingo and warbling show tunes.
And if I recall, we were allowed out too, to swim with turtles, climb the Pitons, night fishing, zip line through the rainforest.
There are resorts, and there are resorts. 
Plus, don't people have a mix of holiday types? This year we've had a city break in London and Venice (DS's choice), a camping trip to Lake Garda with family friends (which had a kids club for younger children, ours enjoyed swimming in the pool and lake), a villa in Spain, and we'll do some survival camping in the mountains later in the holidays (thanks ex army DH
) which DS is also looking forward too.
Now that he's older DS does have a say in our holidays, not always the destination, but as a member of the family we'll look together at things to do and he'll pick one or two that sound good to him. This week he picked some caves with an underwater lake and a glass bottom boat.