There's no such thing as prosperity gospel in Islam. I researched all the major religions when I decided to become religious in my 20s. The prosperity gospel even in Christianity has very loose / 0 underpinnings in any actual theological study.
The Gulf countries became wealthy because of oil. They don't really hoard that wealth though. They are pretty famous around the world for investing that money, no? They fund universities (with many Gulf countries having their own outpost of NYU or other such prestigious colleges), arts and arts museums (there is a Louvre in the Middle East), tech startups, and of course invest in tourism to diversify their country.
They also have many horrible qualities, which are 100% not condoned in Islam like employing slaves in deadly conditions even though all nations agreed to abolish slavery years ago. Or confiscating the passports of foreign workers. Or their ethnostate mentality (similar to Israel where citizens must be of a specific blood lineage even though the majority of people living in their nation are not of that lineage). I could go on and on.
Anyways, Tl;Dr, I don't think they really hoard wealth. They do spend and invest in the world around them and find lots of charitable things (they have rebuilt Palestine a few times now, a very costly endeavor). Also, being Muslim doesn't mean they don't do anything morally wrong by that religion's standard. Same as the many charlatan "priests" of various religions in the world.
The Gulf countries became wealthy because of oil. They don't really hoard that wealth though. They are pretty famous around the world for investing that money, no? They fund universities (with many Gulf countries having their own outpost of NYU or other such prestigious colleges), arts and arts museums (there is a Louvre in the Middle East), tech startups, and of course invest in tourism to diversify their country.
They also have many horrible qualities, which are 100% not condoned in Islam like employing slaves in deadly conditions even though all nations agreed to abolish slavery years ago. Or confiscating the passports of foreign workers. Or their ethnostate mentality (similar to Israel where citizens must be of a specific blood lineage even though the majority of people living in their nation are not of that lineage). I could go on and on.
Anyways, Tl;Dr, I don't think they really hoard wealth. They do spend and invest in the world around them and find lots of charitable things (they have rebuilt Palestine a few times now, a very costly endeavor). Also, being Muslim doesn't mean they don't do anything morally wrong by that religion's standard. Same as the many charlatan "priests" of various religions in the world.