If there were no societal differences between men and women there would be no transgender people. Societal differences meaning everything from gender roles to reinforced behavior from peers and advertisements. Something like a gender agnostic world.
I know that there are plenty of people cis and trans that have a similar view. I disagree with it myself. I think the only way that this would work is if we leave behind physical world and become brains in jars. The jar could be an android body, but it would have to be the same body for every person. I think it's not going to be an issue and even if the technology was there we would find that different people would request different bodies.
On the main point I disagree with the idea that trans people are the result of society and gender roles. The most obvious reason I can think of is that there are trans people across the world in all different cultures and societies over all times, many of them wholly unaccepting and violent to trans people, and yet there are still trans people there. I also believe that the issue is internal and not based on external factors (like society). Even in the most accepting areas trans people exist. We don't want to be a feminine man or a butch woman.
We can see others around us having the secondary sex characteristics that we want or should/shouldn't have. Society treats the groups differently but that is out of our individual control. This is the biggest factor I think in why the only way it would work is if all of humanity was unisex, which solves for society roles and removes all individual sex characteristics. There would be no ability to change how others perceive you in any sense. I think this is entirely unreasonable. I don't think we would be classified as humans anymore.
My thought is that even if we ended up with brains in jars we would still find a way to stand out and want to be individuals. Unfortunately I cannot conceptualize a society that has one sex. I feel like the dividing line would change from being based on gender to being on something else, like being dominant/submissive or accessorizing your android. Those people who wanted to be individuals (in this sense being literally anything except identical to everyone else) would stand out just as much as minority groups today do.
The reason I don't think we would divide on gender in this android future is because I don't believe there is a man or woman essence. There is no 'soul' that is woman or man. In my view I see a group of people that I identify with and was categorized incorrectly by everyone around me. This is part of why some people don't like the shorthand 'I feel like X' because it implies there is some 'X' essence. Other people don't understand it's shorthand for anything and think it is literally a conscious feeling, which it could be, but I think it's more subconscious most of the time. This is totally opinion on my part. There might be research now or in the future that refutes all this.