I no longer travel, but I used to do so extensively and much of what you say rings true.
The breeze block homes are common in many developing countries and the stifling heat (and mosquitoes) can’t be much fun on a daily basis.
The obsequiousness to strangers you mention isn’t limited to these poorer countries, though. How often do staff in our own hotels, bars, pubs and restaurants actually mean it when they smile? Often, they’re just being polite in the hope that you’ll leave them a tip, which they need in order to supplement their derisory wages.
And the biggest elephant in the room is tourism as an industry contributes to climate change, which makes conditions in these countries worse. It isn’t just the CO2 emissions of tourists getting to their location, but also plastic waste, noise pollution, light pollution (which seriously affects wildlife) and even the environmental damage caused by those ocean liners you mentioned on local reefs and atolls.