Okay, first of all, I don't think that you really want to think about this in terms of pixels
Sorry but I fear that this is going to become a rambling stream-of-consciousness essay....
The digital era has trained us to think in pixels... we see pixelated images all the time and sort of learn to accept them. We also review images, more and more, on glowing screens- TVs or computers. But the tonality of a pixelated image on a glowing screen is not directly comparable to that of a film image printed traditionally or a tranny on a lightbox.
Also there are about a zillion different workflows for either route (scanned film or digital), and a lot of variation in the competence of people who do scans, or conversely, digital conversions. I swear to you, I know people who have never shot a film image and see a digital print with that linear tone scale and think it's just fine. I also see crappy film scans all the time. And we've all seen crummy traditional prints too. I think the relative value of the route you pick depends very much on your dedication to doing that particular path with the highest possible care and dedication.
How you compare the relative value of a digital or film photograph depends very, very much on the intent of your final output.
I think what you will find is that the pixel count turns out to be far less important than how much shadow and highlight information you have to work with, and how good you are at curving your source file (be it digital or scanned film) and getting that information into a print.
Now.. on the extremes of pixel count.... I feel that when I have 6x6 slides drum scanned I get ~30+ credible megapixels, easily. And those are 30 million
coloured pixels, not Bayer interpolated. So certainly I feel that my mamiya 6 can go head to head with just about and dSLR on the market, in terms of $/pixel or just in terms of total pixel count per "capture." But frankly, that's only in that fairly limited and specialized ~ISO 100 arena. At ISO 1600 my film is toast. I have ISO 1600 images from my baby travelcam, a Nikon d40x, which are far cleaner than anything I've seen at that ISO from colour neg film in
any film format. And I do shot 5x7 and 8x10 trannies so I know of what I speak
But b&w is a different game altogether.... in that case, tonality and dynamic range take center stage and think film does indeed still have many advantages in almost any format and any ISO. There are still very good reasons to shoot 35mm b&w film, no doubt about it. But there are also good reasons to shoot a colour image on a dslr and do a conversion.
I just don't think that one can compare them (dslr captures and scans) head to head in most cases. They simply have very different strengths, and I think most of us use both.