They definitely don't have equal value. The potential revenue stream for the treatment is much higher than the cure. You have to subtract the probability that someone else finds a cure from that revenue stream, amortized and discounted over its lifetime.

So, it may be that sometimes that causes it to make sense to search for a cure (if there is a particularly promising pathway that someone else is likely to explore, for instance), but all else being equal, it probably makes more sense to fund treatments.

The initial cost of developing any new drug is extremely high. We're talking hundreds of millions to billions. That's just to break even. That means if you have a cure for a disease that 100k people have, you have to charge them each $10k just to break even.

That is insane. The numbers of course scale directly with the number of patients, too. If only 10k people in the world have the disease, you need to charge them each 100k, just to break even (the average cost of developing a new drug is actually 2.5 billion, but for these purposes let's say you get lucky and it's 'only' 1 billion).

If you want to actually make a profit, you'll need to charge even more than that.