Unless I have severely misjudged the quantitative and/or the modal aspects of your thesis, I can't really agree with it, however astute and well-worded it may be.
The same range of fears and insecurities you listed can be (and indeed is chosen by the majority of people to be) dealt with without employing extensive D/s dynamics. Moreover, your assessment completely leaves out most 'casual' practitioners of the fetish that do not try to pursue it as a lifestyle, or base the whole relationship with another person around it.
That's not to say those aspects can't one of the reasons for someone to embrace the fetish. Turning the discussion back to TiTS, Sera, being the most content heavy and developed practitioner of D/s in the game, heavily has content that heavily hints at the exact line of reasoning you have listed for potential Doms. Depending on whether or not her sub content will become canon in-game content, she can also swing pretty hard into the mentality you have portrayed as the basis for typical sub behavior, with PC commenting on and lampshading it. However, her other character traits feed into and modify both of the potential power dynamics she may have with the PC to a great extent, so subSera and domSera end up, for the most part, being their own things.
In the end, I will have to echo IVIP and state that for every person engaging in a kink, things that they get from it are different, and even trying to dig deep into the inner-working of a typical human mind won't provide you with a universally applicable answer.
Lastly, I will ask you to abstain from using arguments based on the idea of 'taught'/'normalized'/'instilled' gender roles, because they fail to meet the criteria of being self-sufficient and evident to the other participants of the discussion. But they rarely fail to start a flamewar.
Given how this subforum is for the game TiTS, I'd suggest posting any similar threads on the general subforum unless it discusses how x issue is handled in the game.
Flagged the thread for moving, might be a good idea to have multiple people do the same.