Indian Railway appears to be purchasing Bullet trains that suits to Japan but not so much to India.
(1) Japan has a very large population of 75-100+yrs bracket many of whom may travel on wheel chair and they have provided separate wheel chair bound paxs. How many wheel chair bound paxs travel on IR is eny body's guess. These spacious toilets shall eat much of the precious space in bullet train and shall serve little purpose.
(2) Japan have negative population growth and is grappling with growing percent of old age persons...
more...

and shortage of young ones who are supposed to maintain the great legacy of Japan in future. Japanese govt want their citizens to reproduce and hence pamper the breast feeding mothers with child feeding room. But India on other hand is burdened with ever increasing population and population growth is the biggest problem of India which the rulers keep at the back burner for vested interests..
(3) Above 2 arrangements by Japanese reduced the number of seats facilitated in their bullet trains resulting in increase in the fare of bullet trains which their rich population can well afford to. But in India, the bullet train shall be out of reach of atleast 90% of population of the small region. The higher cost shall lead to much lower traffic on the route than the break even figure of over 1,00,000 paxs per day
(4) Use of standard guage shall ensure that it will be an isolated network which shall be useful to a very small population may be about 30-40 lacs only. Broad guage could have increased the reach of the Bullet trains and would have allowed bullet trains to travel as a SHS train beyond HST corridor to nearby cities like Pune, Rajkot, etc and long distance SHS trains from Mumbai to JU/JP/BKN/INDB/Delhi etc to use the Mum-BRC-AHM HS network.
(5) Increasing cost and delays in land acquisition shall make the project costlier and hence the fares of bullet trains higher.