Who was arguing that WT doesn’t have an income? Their problem is that their spending exceeds their income.
In particular they have far too many employees. They have enough employees to sustain a worldwide publishing empire that is now all but redundant. I don’t think there is any other church their size that employs so many people to do such a tremendous amount of unproductive work.
It made sense to train and employ missionaries when those missionaries sold literature and produced a net profit for Watchtower. Now it’s a loss all the way down the line. It’s a loss to produce the literature, then to just give it away for free. And it’s a loss to train and pay missionaries (and special pioneers and circuit overseers, for that matter) who no longer sell Watchtower publications.
They are cutting bethelites and missionaries and special pioneers in order to cut costs. But they still have the basic problem that none of these roles adds value to the organisation by their activity. Each and every missionary or special pioneers is a cost to the organisation with no financial return.
They didn’t know how good they had it when growth, preaching, and selling literature were all complementary activities that reinforced one another and strengthened the organisation.