Hart is in part right that increased entrants into the purple markets have driven prices up. But additionally as players have more inf left over after slotting the formerly expensive-ish pool Cs the supply of inf chasing the purple supply is increased, raising prices.
I saw a number of my niches become less profitable as well as crafted IO prices dropped a little and recipe prices saw a slight rise (originally with i18 the IOs stayed stable and the recipes dropped so c'est la vie).
How about you post what they're worth right now and we'll come back in 6 months
Sleep triple's up to 50m from 20m when I started, for example. Hecatomb triple's up to 500m from ~280m when I started playing with those. I'm only on the second month of my sub, so I think this has already happened. I expect the trend to continue as competition for limited supply and the strong profits available through flipping purples push prices up.
What's really driving it though, what's really pushing people with huge sums of cash to invest in high end purples, is greater intensity in the less profitable markets driving down margins. I used to flip ~15 IOs a day at 20-30m profit each, for a net income of ~500m daily. Now I can only manage ~10-15m profit on the same market because of increased competition, so I have to move into more expensive markets where the cost of entry is so high that competition is minimal in order to make the same income.