Levities were called into special service. Some lived from tithe offering given by the people.
In some cases, apostles and other missoionaries, teachers, prophets and elders received economic help from other believers - 1 Corinthians 9
We must distinguish between God's gifting and calling of men and women into service as a paid minister. Being paid and servicing God as not nessarily bound.
Simply because you earn a degree in ministry and convince a church to hire you, does not guarantee you are doing the work of the Lord
Advantages of parachurches hiring:
1,2,and 4 presuppose the existance of the parachurch
If you call into question the legitimacy of the big church model, then the advantages become less decisive
House churches do not required skill personel, just common people looking to worship the best way they can