The key information is halfway down the page, in the figure that shows the number of new graduates and new temporary workers each year. The number of new temporary workers has been relatively stable, while the number of new graduates has been climbing steadily.
There was a shortage of software developers in the 2010s. The industry hired more people from abroad than there were graduates from CS programs. Still, CS graduates had better job prospects than their peers in other fields. The market responded to the shortage by increasing the supply of CS graduates, and that increase in domestic supply kept entry-level wages from rising faster than inflation.
The job market changed in the 2020s. A country with a more reactive immigration policy would have noticed the worsening job prospects of new graduates and routinely lowered the supply of new immigrant workers in that field. The US could not do that, as American legislators apparently don't believe in such central planning. The government can make employment-based immigration easier or harder overall, but it lacks convenient tools for targeted interventions in specific fields.
People who chose CS when the job market was hot are now graduating in record numbers. You could say in retrospect that the market overreacted and allocated too much resources to software. And it's quite likely that the market will now overreact in the other direction, as it did after the dot-com bust. Immigration policy can help smoothen these market overreactions, as you can get immigrant workers much faster than new graduates. But that requires dedicated effort from the government.
and that is their own "fault" for chasing money. The top graduates will still get good outcomes. It's the mediocre money chasers who would do poorly in a down market.
The exact same thing happened to the dotcom boom/bust. You'd think people would learn.