Letting Governments (or politics) submit to street power, is a delicate thing. What if the street has not-so-liberal demands? Party democracy has been constituted in Germany with the experiences of fascist movements in the 30s... Acknowledging though, that most current Governments fail to provide for global solutions, so 'societal contracts' need to be inclusive and include (or be led by) non-parliamentarian actors.
It all depends on where the ultimate source of sovereignty is grounded. There are downsides to grounding sovereignty in "the consent of the governed" or "the will of the people" — and there are potentially bigger downsides in grounding it in the political party, representative democracy or the consent of the elites.
With apologies to Cicero ... his conclusion was that a stable commonwealth requires balance between the King, the better class and the mob, but a stable balance is always elusive. A King that becomes a tyrant would be assassinated by plotters from the better class. The better class would be chased from office by the mob once they degenerated into nepotism and corruption. As the mob descended into disorder, popular support would empower a new autocratic leader to suppress them. Politics and governance is a continuous process of rebalancing.
Is it a correct understanding that activists are the contemporary manifestation of the mob? A necessary corrective because the better class has become corrupt?
I'd say activists are the contemporary manifestation of the demos, rather than the mob.