Not really true. Being a PM is the most lucrative spot at a fund (obviously besides being an equity partner). Finance is profession with no real barriers to entry until to get to proper elite levels. If you don't distinguish between institutions, you will get a diverse population that has guys that bring home millions (i.e. PMs who got solid alpha or senior traders with an ability to monetize firms edge), guys who bring home a buck as regular sell-side traders or buyside PMs and then there are people who can't even balance their check-book.