> ... groups of people that have a shared concern to come together and make their case to the politicians.

That would be solved by referenda, with their results and number of people affected being presented to the politicians so that they must deal with the problem. Lobbying as it is now in many countries (possibly all of them) has nothing to do with that and to me is just legalized corruption.

Who pays to let people know there’s a referendum they should vote in?

But that shouldn't come down to the money. If only the people who amassed huge amounts of money can influence there is no democracy.

Lobbying does not have to be done via donations.

Otherwise I'm very curious how NGOs can lobby.

What do you imply? To me it doesn't matter if you use a different word for monetary value, be it donation or something else, it comes down to the same, namely money.

No.

Lobbying is not inherently money oriented.