Solutions exist. Few will implement them.
For California's proposed HSR line, there will be many stops; a political requirement for the line. Either the proposed train will never reach advertised speeds, or there will be a lot of bypassed stations that we'll be wasting billions on building.
As for Europe, expansion of the low-fare carriers is expanding far faster then HSR ridership; so much so that the Europeans are trying to slow that growth by implementing carbon taxes to make trains more attractive.