Apple's annual gross profit was $195B last year against an R&D budget of around $35B. So, they've got more than enough spare change to throw around. I'm sure whatever they're spending on foldables isn't impairing them financially in any way.
I'm more concerned for what it means for focus, fragmented ecosystems, user experience, etc.
From Jobs: "People think focus means saying yes to the thing you've got to focus on. But that's not what it means at all. It means saying no to the hundred other good ideas that there are. You have to pick carefully. I'm actually as proud of many of the things we haven't done as the things we have done."
The market && apple's choice of either pricing it aggressively or pricing it so that nobody can afford it. Both have equal weighting here.
The Z fold has succeeded enough that I see it out and about even outside tech-circles. Oppo and Google have had multiple generations of well-recieved folables too, despite not nearly having the marketing machine of someone like Apple.