Who. knows. If dynamic pricing is introduced, all sorts of possibilities emerge - especially now that companies are adopting new work practices (e.g. 80% of employees working from home on any given day, with staggered commuting times etc. ). For long distance rail journeys, it might be possible to influence foreign visitors to travel at times when the rail services are underutilized - and disincentivize travel at weekends or national holidays, when capacity is stretched, even with additional trains laid on.
Just keeping my fingers crossed that the Japanese rail companies don't follow the UK's lead with utterly incomprehensible pricing structures, exhorbitant "gotcha" fares for last minute travel, and other jiggery pokery to satisfy the regulators that the operators aren't increasing prices when, in fact, they're gouging commuters.