Around COVID tech gained a lot of popularity and especially stuff like AI/ML became the new trend, so tech companies starting hiring insane amounts of people. In the past year though companies have started realizing "oh shit, we hired way too many people" and started laying off employees (usually the most expensive/highest paid, or the most "useless" i.e. non-tech positions).

It's not really all that bad for juniors especially because now they get a big boost in their opportunities for work, especially ones that worked at the big companies that overhired a ton like Meta, because they can say "I worked for Facebook/Google/JP Morgan" or whatever the hell on there resume, which will make you EXTREMELY attractive to employers and have your application stand out almost anywhere.

At least for software development, you're kind of expected to be hopping jobs a lot because that's the only way you're really going to get more benefits and higher pay (unless you get really lucky and find a company that actually cares about retaining current employees! or you become self-employed which is probably even harder). There's practically an infinite number of jobs, many good ones, in the sphere because of how valuable tech is in the modern world, so you don't have to worry about not being able to find a position when you get some experience. That's why many companies will hire people who barely can even program, so long as they can write "hello world" in JS...

Of course there are other reasons, like outsourcing work, or the company just wanting more profit short-term, or feeling like they don't "need" as many employees since the tools for the job and the number&quality of applicants have gotten better...