Were the first iconpainters monks?

(Fayum portrait from 2nd-4th century AD, technique in wax tempera)

               In newspaper articles on icon exhibitions and icon painters, I often come across the opinion that the first icon painters were monks. This cannot be proved with names. There is another context that makes the opposite plausible:
(a) The painters of the Egyptian death masks from the 2nd to 4th centuries AD, the so-called Fayum portraits, were not Osiris priests either, were they? Yet they painted the portraits for the death cult.
(b) Engravings of the Mother of God are known from the 4th century on glass ampoules from Palestine. An iconographic handbook by a German scholar of repute states without restraint that in the 4th century, after the sanctioning of Christianity, a pilgrimage to the Holy Land began to occur - and these ampoules with the image of the Mother of God with consecrated water (who knows from the Jordan River) were sold to the pilgrims. Souvenir trade! The Fayoum painters or their successors or their apprentices I would say! For surely they had become brodless? Nor should we forget that relics were in short supply at this time. Relic and icon: same emotional value.
(c)You will not find 10 adept painters out of a population of 10,000 monks. One thing is devoting yourself to God, and being useful in what you can, and especially praying, another thing is being able to paint and being busy with it day and night, because that is the painter, he was born a painter. He wants to make money too, and how. The monk has a completely different purpose in his life, he was born a monk. His head would not be on production of souvenir icons.
(d) The magnetism of big money. To get ahead in his career, the painter goes to the big city, patronage and fame. He doesn't stay in Trnovo because his fellow villagers wouldn't give a glass of beer for it yet. Nor can he start writing articles on icons and thus make a living. He goes to Constantinople or to Palestine because there he can work as a painter. Ian Knowles from Bethlehem states that Palestine was at that time one of the most dense populated areas in the Byzantine world. The Fayoum portraits are fantastically professionally painted. So are the (first) Sinai icons. By professionals, in other words, not monks.
e) Too soon we assume a parallel development in the transmission of culture in Eastern and Western Europe. In the East, most probably the imperial court and entourage and the church hierarchy (a constant factor for a millennium) were more important in this than the monastery. Again: the icon painters need not have been clerics. After all, neither were the architects.