I'd argue that the "structural" bottleneck is actually just the same "pay" bottleneck.
This was the whole issue with allowing guilds in the first place... If you only allow a guild to do a job (legally) and the guild also controls how many members they train and accept... The end result is a labor shortage.
Because it's better for the existing members of the guild.
If they train a large number of new members... they spend time and money on training, and they've increased their competition during bidding which drives down rates.
So instead you train the bare minimum for replacements. This keeps your members' rates high and competition low.
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Any time the "pay is great" but the "process to get it sucks!"... you're seeing this in action. It's not that the process really needs to suck, it's that the process roadblocks are there to maintain high pay for the existing trained members.
If there's one thing monopolies don't like... it's competition. And legally enforced certifications are wonderful monopoly creators if you don't manage them carefully.
That's one of the reasons US-trained doctors are in such short supply. The government controls the number of slots in medical schools, and from what I can tell the government does pretty much whatever the AMA wants.
Communists don't like competition, capitalists don't like competition either, what does that leave us with?
Where are the free market advocates that aren't just phonies?
I'd argue that without competition, it isn't capitalism, and before someone "no true Scotsman"'s me, Adam Smith wrote about the dangers of monopolies in The Weath of Nations. Where Scotsman isn't a well defined term, and neither is capitalism, coloquially anyway, maybe, but a free market would have rival trade unions with different certification processes and employers would decide which certification was preferable.
"Neoliberalism" became a dirty word for lots of reasons (mainly because it caused a ton of people in developed nations to lose their jobs, as manufacturing capacity shifted to developing nations and developed nations leaned into the information economy), but there was a time when the word wasn't tainted and the pro-market Democrats of the Clinton era absolutely self-identified as Neoliberals.
They liked competition and markets, delivered strong economic growth, and brought the deficit down, but they fucked up by not funneling some of those efficiency gains into education and training, and toward building a robust social safety net to help the economically displaced.
pro-communists want a system without competition. Pro-capitalists do want competition or at least no restrictions. People who are practicing capitalists would love to not have competition.
Think of a prize race. The people organizing the race and the audience want a highly competitive race. But the racers, if they are in it for the prize, would love to have little to no competition.
Artificial restrictions on who can do a thing is not good and it is violence behind, whether it is government or not.
Anarcho-capitalists are the true expression of the ideology of free markets.
I prefer 90% free 10% preventing monopolies, myself.