Which is not to say that it is perfect or superior to Earth and the larger Federation’s comparatively egalitarian post-scarcity economy, or even particularly ethical.
However, from what we’re shown, the Ferengi political structure (which is clearly part and parcel with it’s commercial structure) does not, with the one HUGE exception of it’s treatment of women, make use of divisive social issues to distract its work force from the disadvantages of capitalism. Unlike contemporary Western capitalism, everyone on Ferenginar from the wealthiest to the poorest appears to operate from the same transparent, if morally bankrupt, ruleset, and the powerful, importantly, don’t pretend otherwise.
This is a dark but kind of brilliant aspect of the rules of acquisition - All members of society, including laborers, are taught from birth to operate from a position of mutual distrust and can operate comfortably with full knowledge that the person on the other side of the table will disregard all other concerns in order to take complete financial advantage of them, and they will do the same. This bypasses a lot of steps that would otherwise be required in terms of building trust or engaging in any kind of sales or negotiation, although there is likely a lot more onus on each individual to do the calculus on any given business transaction internally to ensure that all of their vulnerabilities are accounted for. The phrase ‘trust me’ must be a complete joke in all contexts.
Furthermore, because greed is not just a social value but a desirable and marketable job skill, the playing field, which is horrific from the perspective of most 24th century humans, may actually be more level than even modern capitalism. There’s evidence to suggest that if even the poorest worker can successfully skim profits without leaving immediate evidence behind, this is almost blameless. Quark knows that Rom shaves the latinum, for example.
This is not a complete theory and I’m sure there are plenty of counterexamples, but mostly I just wanted to gripe that shit is so tough irl right now that even working as a Ferengi waiter seems like a dream by comparison.
De facto slavery exists for women in Ferengi society, but the fact that no other apparent slave caste exists along with how quickly Ferenginar’s patriarchy was restructured, if not quite dismantled, I think one possible barrier to an effective slave industry (certainly chattel slavery) is that there would be no concept of a person or group of people who should not be trying to earn profit, and the power structures that exist would not punish an enslaved person who was able to skim profits from any labor or administrative work they performed, nor would it necessarily reinforce their status as a slave if they were able to buy themselves out of their position.
I think Ferengi probably thinks that a person or business can own another person, but I don’t think they can conceive of a person who can’t/ or shouldn’t own anything. This is like how it’s not illegal to attempt to escape prison in some countries - There’s a recognition of the desire to be free.
Now, that’s all a huge problem when Ferengi develop interstellar travel and encounter full-blown slavers like the Orion Syndicate and other criminal elements, because 1) they’ll not only participate in the slave trade for all the reasons you said, but they’ll be really good at it, and 2) they won’t fully understand the power structures beyond wealth which makes enslavement so egregious.
I wonder: Quark’s weapon trading may not have bothered his conscience because of him adopting human ethics, as he feared, but because he was parsing his own ethics with a fuller understanding of the implications of what he was participating in as he was learning more about alien cultures.