They were invented decades ago.
They have fewer moving parts than wheelbois.
They require less maintenance.
There’s obviously some bottleneck in expanding maglev technology, but what is it?
Because it’s not currently profitable in most cases. Capitalism ensures that the merit of an idea comes secondary to it’s profitability. We don’t get the best things, we get the profitable things.
Where existing transit infrastructure exists, cities prefer upgrading existing infrastructure, rather than installing new infrastructure in its place, and where transit does not exist cities prefer not to install anything at all and favor cars typically. Maglev trains are extremely expensive to install the infrastructure, so gathering the money out of local budgets to invest in the extremely expensive maglev infrastructure is typically very difficult.
In the US in particular, politicians, just don’t look at the picture in the long term, and only focus on short term investigator as it pertains to their election schedule, and that is sad and has long-term impact on the local population.
Also for the US the automotive and oil industries have powerful lobbies and an obvious interest in preventing the proliferation of electric-powered public transport. They’ve spent decades centering personal automobiles as the default method of travel and attack these projects with enthusiasm.
I read it’s the zoning and maintenance of the tracks. Since they probably have to be very precisely laid in order to support such a fast train.
That said I do wish for maglev trains to be accessible to all. I’d love to go across the states in a few hours on a train.