Technology

Of course, there are different opinions, but here's my take (as a Swede, but not an expert in politics/history):

The issues didn't start during the last decade. In the 90's, it was politically decided that schools wouldn't be nearly as centrally managed by the state as they had been, instead municipalities would handle most school-related politics and administration locally. It was also decided that parents are allowed to choose more freely where to send their kids. This weakened public schools. Moreover, legislation was introduced (in the 00's I think but I'm not sure) that allows for-profit private schools, which historically AFAIK had been prohibited.

Parents usually don't have to pay anything extra to send their kids to private schools, and for each private school pupil more tax money flows into the private instead of public schools. The private schools are of course incentivized to attract children from families that are well off, since they tend to perform better (boosting the school's score and thus reputation), have parents that can e.g. drive them from a longer distance, and just generally have less issues and so cost and complain less. For instance, it's been reported that some private schools refuse (openly or through loopholes) e.g. special needs pupils since the tax money paid to the school for them isn't worth the cost (and "bad PR", no doubt) of actually giving them a proper education.

Sweden has also had a high rate of immigration the last decades. Immigrant parents understandably tend to not be as savvy about the school system and have less time/resources for getting their kids to "nicer" schools further away. Immigrant kids also tend to require more attention, both due to needing to learn Swedish and because psychological problems, e.g PTSD, are more common among many immigrant groups. Also I haven't seen any studies on this, but IMO the private schools' advertisements (on billboards etc) tend to be very geared towards "white" kids/parents with no immigrant background.

In 2007 a tax benefit for "homework help" among other things was introduced, halving the price parents have to pay for private tutors at home. This again benefits families that are well off and lets private companies in education siphon tax money.

All this means a cycle of segregation seen in so many countries. Public schools are burdened with students that require more resources, while private schools do everything they can to snatch up low-maintenance pupils. This makes private schools seem to perform better and gives public schools bad reputations. Racism and class discrimination also plays into all this of course.

It also doesn't help that teachers' salaries and social standing have decreased, partly due to the same general patterns.

This degradation of the public school system has continued during both left-wing and right-wing governments, though it's often accelerated during right-wing governance. For instance, the social democrats party was the one to push in the 90's for shifting responsibilities from the state to municipalities. There is an ever growing issue with corruption across the political spectrum (but worst/most blatant on the right), where it's become quite common for politicians to push for decisions that benefit private companies, then retiring from politics and joining said companies' boards etc.

This is only a guess, but it could be related to increased use of technology. Many things we interact with are simplified, and if you come across a word you don’t know your phone can give you simple synonyms or if you can’t spell autocorrect will catch it.

The same problem people are talking about with LLMs with a different lens.