First, unions don’t prevent mass layoffs. They might help make things more manageable and help some individuals in need but layoffs are entirely at the discretion of the business.

"There are several ways that unionization’s impact on wages goes beyond the workers covered by collec- tive bargaining to affect nonunion wages and labor practices. For example, in industries and occupations where a strong core of workplaces are unionized, nonunion employers will frequently meet union standards or, at least, improve their compensation and labor practices beyond what they would have provided if there were no union presence. This dynamic is sometimes called the “union threat effect,” the degree to which nonunion workers get paid more because their employers are trying to forestall unionization.

There is a more general mechanism (without any specific “threat”) in which unions have affected nonunion pay and practices: unions have set norms and established practices that become more generalized throughout the economy, thereby improving pay and working conditions for the entire workforce. This has been especially true for the 75% of workers who are not college educated. Many “fringe” benefits, such as pensions and health insurance, were first provided in the union sector and then became more generalized—though, as we have seen, not universal. Union grievance procedures, which provide “due process” in the workplace, have been mimicked in many nonunion workplaces. Union wage- setting, which has gained exposure through media coverage, has frequently established standards of what workers generally, including many nonunion workers, expect from their employers. Until, the mid-1980s, in fact, many sectors of the economy followed the “pattern” set in collective bargaining agreements. As unions weakened, especially in the manufacturing sector, their ability to set broader patterns has diminished. However, unions remain a source of innovation in work practices (e.g., training, worker participation) and in benefits (e.g., child care, work-time flexibility, sick leave)."

https://www.epi.org/publication/briefingpapers_bp143/

https://files.epi.org/page/-/old/briefingpapers/143/bp143.pdf

i can guarantee that nothing can stop a business from maximizing profits.

You are not a union, you cannot stop a business from doing anything, together with your fellow workers however you can dictate anything about the behavior of your company that you and your fellow workers feel sufficiently passionate about enough to fight for.

And second, the industry is contracting because it hasn’t innovated in more than 5 years now.

Why should an industry bother innovating to increase dividends to shareholders with expensive and risky new technological ventures when it can just keep slashing labor costs and crushing employees under their foot? There is no economic incentive to innovate when unions don’t have the power to make executives think about choosing other less difficult paths than trying to directly reduce the quality of life of the companies employees.