Even if I buy the premise that our trade relations with China weren't working, doing something objectively worse doesn't somehow make a bad situation better. I'd further suggest change for change's sake, especially done with an eye for bombast, is not a prudent way to approach international trade deals. International trade negotiation is extremely complicated and nuanced.
Setting that aside, the reason why there isn't more of a push against China by more nations is because, rightly or wrongly, they have a lot of power in the relationship. Multinational corporations both value a cheap labor force and access to their market, and these corporations heavily influence their nations' trade policies. China knows this, they aren't fools, and as a consequence they aren't going to be pushed around easily.
So I don't think it is about being too scared to change things up as much as a recognition that blowing things up won't work because we value what they bring to the table more than they value what we bring. In other words we are not negotiating from a position of strength.
I also disagree with the premise it will be a long time before differences can be evaluated. I think they can be estimated pretty quickly and it can / will be shown that even with the most favorable interpretation of the analyses show a net loss short and long term. What did China capitulate on?