>>2020245JR Hokkaido don't want travel time on Sapporo-Tokyo service be affected by the proposal, including the time it take to (de/)couple the train at Shin Hakodate Hokuto station.
Also, since the platform of Shin Hakodate Hokuto station is only 10 cars long, if it is to decouple then Hakodate will only get like 3 cars
>Cut unti Tokyo Sapporo serviceIt won't, because there will only be something like 5 trains from Tokyo that terminate inside Hakodate City, and they can be achieved by extending trains that currently terminate at Shin Aomori, as long as capacity of Seikan tunnel permit, and that won't be a problem if they end up deciding to abandon Hakodate Main Line.
>>2018663JR Hokkaido emphasize any plans of extending the Shinkansen service into inside Hakodate City must cause zero burden on JR Hokkaido, no matter financial or operational or.
Adding another type of trains onto JR Hokkaido's network is a burden.
And if through service is to realize, then that mean JR Hokkaido vehicles will also need to enter the track, and if it is to be Mini Shinkansen then JR Hokkaido also need to order Mini Shinkansen trains instead of full Shinkansen trains in addition to what Hakodate City will get
As for whether it's going to be oversupply of capacity, surely shortening travel time from 4 hours to 1.3 hours can induce many demands. How much is still up to debate but can probably fill a bigger train.
