I'm confused.
Do you think that access to modern technology and foreknowledge of the lunar environment will make a LM harder to develop?
If not where does the belief that LM 2.0 will have to be significantly less capable AND more expensive than LM 1.0 (even after accounting for inflation) come from?
No, I think it will make it
not much easier than in 1963 to develop a LM. That is a difference. We have no LM construction kit anywhere. We have 50 years without ever constructing something like a LM. Where would we pick up? Sure by what we know by constructing orbital vehicles and unmanned landers.
And nothing of those two sources of experience shows a significant revolutionary cost reduction to be possible in the development, only a evolutionary.
Also knowing more does not mean you know how to make something cheaper. Unknown, unknown problems are the keyword there - problems that you have not even been aware of at design time. When the LM was designed, we did not even know how the surface of the moon is really like. Or how problematic the dust on the moon will be. Those are today known problems, for which you have to prepare. And for which you need to design and test. This means you have in the end higher KNOWN costs in advance. And simply less costs that will be added later in the program when you find out. In hindsight, your program might be cheaper in total. It must not be. But you sure would have more reliable cost estimates when you begin. And those are higher than by ignoring the previous experiences. You could ignore them. But then your quality would shrink: The original LM was pretty lucky in many aspects, its shortcomings did never turn out bad (Except nearly leaving the crew dead or stranded in some instances - just think about the broken switch issue). But the more was known about the spacecraft during a mission, the more was known what would be needed to be modified.
Finally: If you want to reduce costs, you need to reduce performance or quality. And in spaceflight, you can't reduce quality a lot without killing the crew. If you want to make your LM 2.0 significant cheaper than the LM 1.0, you need to reduce performance. And half or even 1/3rd of the original costs (accounting inflation) is a significant cost reduction.
if you would try to build something that is exactly performing like the LM as flown during the final J-missions, you would maybe even end with just 20% cost reduction. Where would the cost reduction come from? The parts are maybe smaller and lighter and you could sure build the same spacecraft with a fraction of the mass budget. But you would still need the same kinds of subsystems. You would need to test for the same number of specifications. The actual costs of the parts are only having a small contribution to the total costs at such a small number of spacecraft. Also you can't underperform in design, when you have to replace the Apollo subsystems by COTS components. What you save on designing the individual components does not reduce the costs for the system design. If you don't need to design your own IMU, you save a lot of R&D costs. But at the same time add new costs for fitting the existing IMU into your design.
Regardless how I play with the coarse numbers in my head - I can't really see any reason right now to offer less than 20% cost reduction from the original 3 billion at the same specifications - 2.4 billion.
And about 30% mass reduction - you could land two astronauts and a significant scientific payload including a LRV, about 450 kg/1000 lb likely with a spacecraft weighting only ~11500 kg at launch, using some modern structural design and modern components.
If you want to further cut costs by making smarter design, you have a new requirement analysis phase, with additional costs initially. But then you could get down to the numbers I stated above. Instead of just taking Apollo components and replace them by modern components, you design the subsystems for modern components. Then you could likely get the mass below 10000 kg, at the same crew, payload and endurance targets. You could redesign the structures completely (and not just take Apollo and adapt for available metal specifications), use 3D printing at some critical places, etc. Then we could also really make use of CAD and CAM, something that was in its early developments during Apollo.
And yes, that would be a new spacecraft. Brand new.
I refer to here for the original and improved specifications - and what was later planned. Considering your add-on development background, I am sure you know it already, but maybe others reading the discussion have not:
https://www.hq.nasa.gov/alsj/LM23_LM_Derivatives_LMD1-13.pdf
