I began attending engineering conferences on integrated passive components around 15 years ago. At that time, there were various schools of thought ranging from integrating resistors, capacitors, and inductors on a simple ceramic chip or chip array, to embedding resistors in the printed circuit board, to bringing multiple passive circuit functions onto the silicon of the IC they were associated with.
In particular, one large OEM gave many presentations showing the feasibility of embedding resistors and capacitors into the PCB (printed circuit board) structure. Their conclusion was that embedding passives into the board would save some amount of cost for resistors and capacitors with somewhat looser tolerances and for circuit designs that had completed prototype validation runs.
Yet today, I still see very little of this type of design happening. This may be a little surprising to some, given that embedded resistors are now able to hold much tighter precision, their cost has gone down, and design for manufacturing has become more advanced with the boundless simulation software programs now available.
However, in my opinion, the increased complexity required in the PCB (or silicon if the passive functions are brought aboard the ASIC), compounded by the fact that discrete commercial passive components are so abundant and inexpensive, means most design engineers simply don't want to deal with the added issues of these more complex boards and ASICs.
I just don't think the benefits outweigh the risks, but this is from the perspective of a passive component manufacturer. I'd be very interested to hear other opinions on the subject.