I am unsure how someone might think lobbyists don't generate value. With their lobbying they convert causes which can't be easily utilised in the democratic process to be more addressable (which means: can be targeted by polarising groups in either gov or opposition)
They do extend the capacity of democracies dramatically.
eg: Nobody linked mahogany with dying rainforests before Greenpeace.
You're confusing lobbying with political activity. Greenpeace's power comes through citizens, advertising, and information, not lobbyists. They have 250,000 members in the US and are widely known and quoted. But last year they spent only $30k on lobbying out of the $3.2 billion spent, or less than 0.001% of the total.
They do extend the capacity of democracies dramatically.
eg: Nobody linked mahogany with dying rainforests before Greenpeace.