Bernie was saying the same things before Trump showed up - this is a general trend, not caused by anyone in particular.
It took Trump yelling about it from the rooftops for over 5 years, and getting over half the population as passionate about it as he was, and then Trump actually doing things about it while in office, for things to actually happen and be set in motion.
You also don't account for the fact that there may have been a negative change in trajectory of that particular metric if not for Trump's policies and executive actions.
But, again, he absolutely did do things about it, these are all well documented. (As is the change in trajectory of public opinion towards offshoring thanks to Trump promoting them heavily.)