Well, that’s time (or deferred pay) they’ve contractually and morally earned, so that part’s entirely fair.
In the U.S - where you generally don't have to pay as long a severance pay if at all.
on edit: as in most things 'in the U.S' this varies on state by state basis.
Does Denmark not have constructive dismissal laws? Making changes that force someone out is an easily winnable unfair dismissal at an employment tribunal, at least for the UK. And that costs more than just firing them for bad performance.
You clearly haven't met Austrian management. It's nearly at will employment (in theory it's not, but in some domains many companies know and do skirt around the law to get rid of employees quickly without getting sued).
Once the management decides they don't like you anymore, you're given your standard one to three months notice, then you're gone. I asked a lawyer, and they said the employer can fire your without any reason as long as they give you your contractual notice period.
My favorite example is them using Jira velocity charts to fire the one with the slowest curve. You get a warning (p.i.p.) telling you your velocity needs to catch up, then after two sprints you get your notice handed to you.
OTOH, there are other EU countries where firing people is really difficult. Here it's just a rubber stamp thanks to decades of pro-business politicians elected in power who eroded workers' rghts.
In many English-speaking countries is not difficult to convince an employee to quit.
When you fire someone. You tax HR and yourself with the process both of letting someone go and finding their replacement. You have to pay their salary 3-6 months going forward as well as all the paid vacation they may have saved up. Most importantly you tax your team with the added resource drain of covering the tasks as well as integrating the replacement. You also risk damaging morale, and worse, you risk increasing employee anxiety as even the best employee can have inferiority issues.
That being said, the basic mantra in management should always be that you can get rid of anyone, it’s just a matter of cost. So if you need to fire someone, then you need to fire someone.
Personally I prefer building people to the point where they will leave you themselves, but, that’s a style or management that isn’t present in a lot of companies because it takes a corporate culture that is very hard to maintain in large organisations and require quite a lot of management talent in small organisations. It’s also something that is incredibly hard to do as a single manager if the culture is against you.