First of all Mowla Ali AS was a poor man. Moreover, he could have given something of value to the Prophet instead of selling it because Najwa does not have a figure. Qur'an says, give something. Something does not mean money. I doubt that he offered him najwas throughout his life for consultation. I doubt he needed so many consultations in the first place.After revelation of this ayat, Maulana Ali was the first person to uphold this. He sold something of value to get money to do najwa to the Prophet(SAW) and he maintained this habit throughout his life.
Whether Bohoras consult the Dai in private or not they are forced to give najwas. First of all, Najwa, according to the Qur'an was for the Prophet SAW. And in the absence of the Prophet, it could be extended to the Imams. And if the Imam is in Satr, a Dai is not to collect Najwas because Imam is present in Satr. Even if the Dai is sitting in India, Najwas will be collected around the world every Ramadah, Mohorram or for any other excuses.
No pious Muslim man I know does that. No muslims are forced to give Najwas to their preachers who can be compared to the Dai. Preachers are missionaries and the word Dai means a missionary and nothing more.