I've worked with many UK/Europeans. They are quite similar to us in skills and productivity aside from labor laws(excessive vacations, months/years of parental leave, impossible to fire etc.)
A good reason that often doesn't qualify is that business is down, macroeconomic conditions are expected to be unfavorable for the foreseeable future, and expenses, which for many businesses are dominated by salaries, need to be cut ASAP to ensure the business' long term survival and prosperity. Like now. Businesses in Europe simply have fewer options, like it's much harder to cut early and cut deep(hopefully minimizing future cuts) when trouble is ahead when you have to have protracted negotiations with unions and government agencies who have to sign off on your layoffs.
Union negotiations are about how to organise the layoffs, not whether you can fire the workforce or not.
And if you expect help from the government, you need to show that your layoffs actually have a chance to make your company survive. For example, you cannot fire the entire R&D when you are 1 year from product release.