Of course you’re entitled to your view but I consider that an egregiously cynical take, not to mention a bit convoluted and with a hint of conspiracism. The fact remains that the Republicans are offering more money to them, up front, now, so the simplest explanation is that they are motivated by higher ideals than just money.
It was never popular even in France, for a simple reason: the week became 10 days but the weekly rest day was still only 1.