Often, buyouts terms are more generous than layoff terms. Even if the company has a history of generous layoff terms, the next one may be less generous.

The other thing to consider is if you'll want to keep working at the company after so many people have left due to the buyout and the layoff. If not, taking the buyout and looking for a new job is likely to be better for you than not taking the buyout, not getting laid off, and looking for a new job once you conclude you don't like the new environment. For one thing, you'll probably have buyout compensation and new job compensation at the same time; for another, it may be easier to find a new job if you're in the market before the layoffs increase the hiring pool.

buyouts usually imply a far more generous offer than just termination and severance.

also means they can dodge any NDA / wrongful termination / bad behavior issues on the way out. sign the doc and play nice and get $$$.

keep in mind the US doesn't have great protections in that regard, so "severance" may be them allowing you to collect the last of your crap on the way out and paying you through the end of the week.

The first layoff or in this case the first buyout is probably the most generous one.

Layoff severance isn't great and it's very common for companies to use the performance system to get rid of people. Suddenly someone stops meeting expectations and are gone within weeks.