Now the riposte can be - "Hey...we'd have had mass mobilization anyway with or without Gandhi"
Maybe. But it might have been a more violent form of mass mobilization (quite likely Communism or a milder variant of it)
But no
1952 elections, the first universal elections held in India, gives us a clue
The "Gandhian" Congress party got 45% of the vote
Left parties of different hues got 23%!
Hindu Right < 5%
Not to the Right
I still regard the peculiar nature of Gandhian mass mobilization as one key reason why India did not lean to the too far to the Left in early-mid 1900s
Sure
But Tilak's brand of conservative politics might not have had a lot of success in 1930s India outside of Western and to a lesser extent North India
An interesting case study is Madras Presidency
Where the pre-eminent leader from 1930s to mid 50s was a rather aloof brahmin - Rajaji
And TN remained a Congress bastion till 1967!
There is no way that would've happened without the "nationalist" movement
It would've turned Dravidian much sooner
The Left was popular
Gandhian nationalism stunted its development