The core reason why high-speed rail projects are prone to losses is that not only are the initial investments extremely high, but the subsequent maintenance costs are also very high.
For India, if it's just about connecting a few major cities, then directly outsourcing the entire project to Japan or France, without investing more funds in research and development and manufacturing of high-speed rail, would be the most economically efficient option.
However, the Modi government has consistently advocated "Made in India." If India seeks complete self-reliance in high-speed rail technology, this plan will be completely beyond India's capacity and will inevitably fail.
If there are only a few lines, the operating costs will be so high that ordinary Indians will find them unaffordable. It's certain that the fares will far exceed those of air travel, possibly 2-5 times higher. To match airfare prices, India would have to use other economic means or funds to cover the enormous losses. Otherwise, even if these high-speed rail lines are opened, they will quickly shut down due to funding problems.
In the 2000s, China collaborated with Germany to build a maglev train demonstration line in Shanghai. Because the technology and related systems of this line are completely incompatible with China's existing high-speed rail system, it has remained in independent operation.
The system was originally intended as a mode of transportation for ordinary people. However, its high operating costs resulted in extremely high ticket prices. A 29km journey costs 50 RMB. This has turned it into a tourist attraction for visitors rather than a daily mode of transportation. Locals or those who frequently travel between the two locations rarely use it.