Skill proficiency limitations were added in Archeage on purpose. Players need to choose the activities they would like to pay more attention to.
from my understanding, they were added so there would be additional sinks(flakes from gold) and milking money from players(flakes from creds) in the game if players wanted to specialize more skills without alts/hassle/all in one char. (kind of like inventory slots/quality of life/convenience things) - this kind of work towards promoting multi-clienting as well in archeage (more labor, diff acc specializes in different things but we cant do that here). and yes - they do help you to focus on certain specializations so people are able to get to higher tiers faster in a sandbox game.
Skill proficiency limitations help promote trading of services and goods in the game. If players can do all professions to max capacity then it will have a negative effect on the economy.
by that line of reasoning, no one would be trading basic/low prof tier mats as anyone can get them by themselves (just because you can get/make it yourself, doesnt mean you will - most people buy if they have the means) - especially true for higher tier stuff as it saves you the hassle. also, majority of high volume goods being traded does not need high prof so it does not reduce trade volume even though everyone can do it.
and the fact is players can get all proficiency to max capacity, just not on one character. proficiency is not shared between characters so you can just swap characters. (now dont go and say we dont need this because if so, we dont need higher stack amounts now do we?) also, only players interested in maxing out proficiency will do that and that requires you to burn 230k labor in all fields.
for the promotion of services, i assume it would be something like making an animal pen(locked behind 230k of husbandry). now, wouldnt it be more likely that said person looking for services will be more likely to get it, if i had it on my character and i do not have to swap characters to render that service? / my proficiency not being hardcapped.
also, if you are talking about someone who can make everything by themselves and therefore do not buy stuff from others, that means said person will need to sink in 230k labor into everything which takes a significant amount of playtime, land etc etc, wouldnt that actually benefit the game? (im convinced that at some point there would be just mass buying of mats to grind prof / actual production of mats from some of the obscure professions like artistry,construction etc / more mat sinks) before they reach that point.