Why do McIntosh come with cheap plastic remotes?

For one thing, plastic is light and fairly resilient. I think a lot of members and professional reviwers make far too big a deal of the way remotes look and what they are made of.
Complaints about the way they are layed out or how they function are valid. Poorly designed remotes can be annoying.

Agree with Hansk46 and Theo, ARC take the cake for cheap remotes that are not remotely commensurate the with quality of its components. The remote for the CD-8 is an embarrassment. Why not add ARC to your thread title? The McIntosh remotes may not be perfect, but they're nicer than ARC. OTOH, compare, for example,Conrad Johnson's fine quality remotes (at least for my Act 2.2), now there's a company that accessorizes with pride.

Have to disagree that the remotes are somehow substandard. Both of my new Mc units (C50 & MVP881BR) came with back-lit remotes that work very well. The soft-touch coating on the plastic has a nice feel and doesn't collect dust like the NOS replacement remote I bought for my MAC 3. That one wasn't back-lit and had a glossy metal function ID plate on the top. It scratched the moment I wiped dust off it. All the remotes are readily replaceable through Audio Classics at about $50 or so. Considering the cost of the equipment and how quickly the magnetic contact closures fail regardless of what the external housing is constructed from, I feel Mc has done a smart thing.

I have three Audio Research devices. A REF 3 Pre-amp, A DAC 8 and a Phono 6. They all have the same type of remote. Although they are ridiculously heavy, remotes made from a solid block of aluminium like some, I believe that AR concentrated (correctly) on the actual equipment, like the amp, pre-amp, etc. The remote doesn't matter much to me as long as it doesn't fall apart and that it works correctly. Which they do work correctly. If you want a hefty, solid remote like Boulder equipment, they remember, you will pay for it. I don't believe it necessary to add to the price for this extra.

Does it work? Does if fail or break easily?

enjoy

The remote quality issue becomes really important to me when certain functions can only be accessed from the remote. If the remote dies the gear can become useless.

For older gear it can be impossible to obtain a replacement should that become necessary.

Sometimes I order a spare as a backup (while I can) and also program a universal for normal use.