In normal operation, an aeroplane lands with enough fuel for one go-around and re-attempt at landing at the chosen airport, plus enough for diversion to their alternate, plus an additional 30 minutes of flight.

If an aircraft is anticipated to land with fuel for 30 minutes or less they must make a mayday call, and there's an incident report to fill in.

Yes they want to land with as little fuel as possible, but regulations require them to carry more because we know what happens when you let airlines carry less.

That's not really accurate. Commercial airliners typically land with significant reserve fuel remaining on board. If a post crash fire ignites and isn't rapidly put out then that reserve fuel will be plenty to destroy the aircraft and kill everyone who doesn't evacuate quickly.

https://simpleflying.com/minimum-fuel-requirements-definitio...

Less than a full load certainly, but I wouldn't say "little fuel". 30 minutes fuel remaining is an automatic mayday call.