I think once the DFCs are up-and-running within the next several years, the commercial lines will be decongested and will skyrocket to 160kmphs. Then after that is the next step: bullet train. Also the average speed may be artificially lower because it incorporates slow local trains in Mumbai and stuff but I'm not sure
DFC will decongest the Passenger service - True.
Skyrocket to 160 KMph - False . For that to happen we need to upgrade both track and signaling systems. (Using continous welded rails, banking changes, advance signal like DFCCIL , Metro etc.)
Bullet train - Even current one takes 4 years to complete. We are going to complete the GQ Shinkansen only by 2051.
We should start categorizing trains
Upto160 KMPH - T18,Exisiting trains will do the job when you upgrade the infra.
160 - 300 Kmph - No current product - 230-250 kmph is a sweet spot of operating cost and ticket cost.
300+ - Shinkansen n700 series- Operating cost and ticket cost will be higher.