As for as storefronts go, which is what's being talked about here, they are competing and winning. With a fraction of the employees other companies employ for storefront work. Origin (Rest Unpeacefully) and Uplay never stood a chance and epic has had plenty of time to market saturate. The company not being publicly traded doesn't prevent competition, it prevents investor interests like quashing competition.
They've touted before that they may be the most profitable company per employee on earth. They make a few billion in profit per year with a payroll of a few hundred employees.
I don't know, there's plenty of anti-Valve rhetoric on Lemmy. Plenty of people try to spin it as Valve having a low employee count because they have a lot of contractors. One guy was making a point that Valve employee count is much lower because they buy in AMD GPUs for the Steam Deck... As if Valve should buy chip manufacturing plants and design and manufacture their own GPUs.
Even here somewhere below (or maybe up later) in this thread someone said
Also, a company can pretend to have 10 employees if it instead hires 1000 contractors to do the actual work.
Which is an argument, if you can prove Valve is buying in 10 times the amount of contractors as they have employees for positions that should go to full-time employees. But I very much doubt such information exists.