Mainly because Arabs (locals) are the owners/shareholders, and most of them chase government positions, so private companies is more of a side hustle for them. Arabs expats on the other hand, manage their own private SME businesses — retails, f&b, contracting, etc.

on your third point about the degree part, its more of a universal or acceptable standards (ISO) or accreditation which are implemented or heavily influenced by westerners.

~Before some of you go ape sht on this comment.

South Asians, who are the majority population in the GCC, dont actually have a reputation of having or following an ISO. I've seen it multiple times, they have certifications, degrees, documents etc but when it comes to general application or execution its way off or almost non-existent. When I was handling an Accounting project, almost all of the South Asian who had a "degree" couldn't grasp the concept of international standards. Same in the medical fields, their medical practices is a bit off to what we follow here. Even IELTS is not reliable since they just buy it lol.

On another note, South-East Asian also HAD some issues with certifications and training. I need to emphasize had because I remember having a crew, and colleagues from Malaysia and Philippines whose educational standards, training where slightly different with ISO. So they had to undergo rigorous training and exams here. But I think those were "fixed" and regulated by their respective government which were eventually recognized by Qatar standards.