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?
Here’s an interesting write-up about an attempt to develop a large-scale urban maglev system in the 1970s: https://en.wikipedia.org/wiki/Krauss-Maffei_Transurban
tl;dr: there were so many technical issues that when the West German company developing the tech lost funding and the Ontario government took over the project, they immediately abandoned the maglev concept and replaced it with linear-induction propulsion with steel wheels on rails (the mag, without the lev).
Even this tech, which does have a few advantages over conventional rail and is still used today in cities like Vancouver, is falling out of favour due to general logistical issues with using bespoke technology over conventional rail – fewer people know how to build and maintain it, you’re relying on usually just one company to supply your trains and infrastructure until the end of time, you can’t reuse any existing infrastructure, etc. I’d imagine these issues still get in the way of maglev development today – even more so because you can’t even reuse existing rails
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.
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.
