Yes 5 year old boys and girls should wear diapers.
Especially 5 year old boys they should be wearing diapers all the time because at 5 years old they can have wetting accidents and wet their pants before making it to the bathroom.
Having a wet diaper is much better than having wet pants.
I wish my parents made me wear diapers at 5 years old but sadly they did not.
Kids don't need potty training and if they want to use the toilet then they can but if not they should wear diapers instead.
Diapers are better than using the toilet and it's better to wet in a diaper at 5 years old, 6 years old, 7 years old, 8 years old and beyond than to hold the pee.
When I have kids they are never gonna be potty trained and will wear diapers all the time and I will change their diaper even when they are 8 years old, 9 years old, 10 years old and beyond as long as they live with me.
No toilets for them and diapers it will be.
I don't use the toilet anymore myself and use diapers all the time as an adult.