That's like asking "how long is a piece of string?"...
Huge chips pushing the maximum reticle size like Nvidia and Intel and Xilinx used (700mm2 or so) have the advantage of being monolithic so not needing any inter-die links, but the yield is *terrible* so the cost per mm2 of silicon is high -- and this cost dwarfs any adder for multi-die chiplet packaging, even if silicon interposers are used. There's also the issue that if you want a family of parts you need a family of chips, and have to pay the development and mask costs for each one which are huge nowadays. With chiplets TTM can be quicker, and spinning out new family versions only needs new interposer/package which is *way* quicker and cheaper than a new chip design.
Depending on what the application is, the inter-die links with chiplets may have almost zero, a small, or a large penalty in performance -- but for big devices a single die will always be more expensive to manufacture, and harder to ship in volume because you throw many bad die away for every good one, some of the biggest chips have single-digit percentage yields.
So if your application values performance over everything else including design/manufacture cost, flexibility, TTM, and high volumes, and it will fit on one big die, and you can sell the end result for a high enough price, then single-die is the way to go. This is what Intel used to do, and why their market share is shrinking.
If cost and flexibility and TTM and big volumes (high yield) are more important, or if it's just too big for single-die, then chiplets are the way to go. This is what AMD have been doing, and why their market share is growing.
There are other advantages to chiplets such as being able to mix different technologies optimised for different functions (e.g. CPU/DSP core vs. SERDES/IO) and not having to make or buy all the (increasingly expensive) IP you need on one bleeding-edge process.
As the cost/effort of each chip development has gone up with each process node, the market is moving more and more to chiplets to keep cost and headcount under control, especially where you want a family of parts not just one.