I think you misunderstand what peaceful unification actually looks like. There was no way that Taiwan would ever peacefully reunify with the think that "Yey, we are Chinese, and China is so good for us, so lets unify". This type of friendly peaceful unification was never in the cards. This goes against the nature of human beings. Every single separate government would always try to maintain separation and independence as much as possible. Human beings never give up power without coercion. When Taiwanese got seperated due to civil war. They got power to forge their own way. They got their own military and government. They simply have no reason to give up that power.
Not only that, in order to keep that independence, all leaders and elites of a region or a country will try to maximize that seperation by separating cultural similarities, making up alternate histories even creating policies to change the culture to a different one. These are all strategies that have been done in the past in many breakaway regions.
The only way China can take back Taiwan is by demonstrating that they either give up and surrender or lose everything, including their life. China has to make an offer to Taiwan that they cannot refuse. Only with that kind of coercion is a peaceful unification possible.
If you read the history of Hong Kong negotiations, it was the same scenario. British tried many strategies and arguments to keep ruling Hong Kong. China made it clear that they can take Hong Kong in an afternoon. They said unless British made a deal with them, China will announce its own plan and execute it alone. Then Britain had no choice but to accept doing a deal. Then beijing gave them the carrot that, in order to smooth the transition, there will be a 50 year one country two systems. Then Britain agreed because it was either this carrot or the stick of Chinese invasion, destruction and British humiliation.
When China gets strong enough to make it absolutely clear that US is simply too weak to fight a war with China in Asia and win, then China will create absolute fear among Taiwanese that they are doomed. Then a bold Chinese leader will make them an ultimatum that unless they start negotiation with mainland for unification, China will invade or worse bomb them out. The Taiwanese will try to see if they can get help from outside countries. It could be Japan, US or EU. Once they see that they have no help and no way out, then they will decide that negotiating a unification that preserves some of their freedoms is better than a hopeless war and destruction and suicide.
That's how peaceful reunification will happen, through Chinese strength. Not happy happy I am so nice attitude.
