What you have described is what is happening in the US except it usually starts at 10+ years. Companies hold severance over your head forcing you to do a "knowledge transfer" to your younger, cheaper replacement.
What Stupid American Companies don't understand is that even if it were possible to transfer ten years of experience in 30 days that you have no incentive to do it based on how you were treated. After all, managers neither know nor care about the many technical nuances that you have mastered over the last decade and keep in your head. It's the "stuff" that's not in the documentation that you learned through trial and error that makes you valuable and there is no way to measure or quantify this "tribal" knowledge that gets handed down from person to person. The literally do not know what they don't know.
Furthermore, they have taught the new hires that loyalty and tenure means nothing and that they should jump to another employer the moment they get a better deal.
IBM is actively culling 50-somethings no realizing that it sends a message to workers in their 30's and 40's that there is no long term benefit to staying with IBM and they should leave while they are still young enough to land on the promotion track at another company.
This was posted originally at @P620rRs-1kfc. I think that the OP hit the nail on the head with everything, especially letting younger folks know what's going to happen to them soon. I know I am already looking for a way out, 5 years in.