The only way to reduce the costs of Maglevs is to build a lot more Maglevs. However, it’s not necessary that there actually are significant economies of scale

The only way to reduce the costs of Maglevs is to build a lot more Maglevs. However, it’s not necessary that there actually are significant economies of scale to be achieved with Maglev. But the bigger issue is that it’s not clear why anyone outside of Japan would even build Maglev at the moment. For obvious reasons, faster speed only becomes advantageous beyond a certain distance. But pretty much every country in the world has city pairs where HSR isn’t built out and the distances are too short for Maglev to be built. Any country trying to go in for a high speed transit option is likely to connect these city pairs first before they try city pairs at greater distances where Maglev may actually make sense even ignoring cost. So you’re unlikely to see a mass rollout of Maglev for decades, so the actual correct answer is that what you need to make Maglev more cost efficient is a few decades and economies of scale.