OK, I have got off my lazy butt and done some of my own research. I can buy a used 24 track deck for $2.5K - $3K. Don't know about condition, but I will assume all sellers are angels who only sell perfectly working machines. I will make the same assumption for the HD24; it goes for about $1K used.
In, say, 10 years, I would expect no maintenance costs for the HD24. I might expect one hard drive failure (it has two), so let's budget $100 for that. But I am uncertain whether to score that as maintenance or media costs. Otherwise, the only media cost would be $100 for a second hard drive to start with, since it only ships with one.
So let's say $100 for maintenance, and $100 for media.
Mixdown medium is not relevant, since either the analog or digital recorder has all the same options for that. Other than the firewire option on the HD24, which of course is optional (I don't have it myself, although most do. My PC DAW is too old to have onboard firewire!) So we needn't consider that.
So I believe you are correct, an analog setup costs the same as several DAWs. But if I had three HD24s, I could link them for a 72 track setup, or a 48 track setup with a backup machine. And if I add in the maintenance costs pipeline mentioned (let's say twice in ten years, about half as often as he stated), I'd expect I could save enough for another HD24 in that period. I'll be nice and bill out all media costs to the clients and not ding analog for that. I am also ignoring any additional labor to calibrate and maintain the analog deck.
So, in summary, analog is about 4x as expensive as digital--likely more like 5x to 6x, but I am being nice.
Lucky for me, I have a 24 track 2" MCI, 2 Fostex 16 track 1/2", 1 Nakamichi cassette and a Studer 1/4" mix down R-R. My dig system is a Fostex D2424LV 24 track HD.
I record on whatever the people want. The sound is not even an issue as I can't even tell over time what is recorded on what (except the Fostex E-16s).
The reality:
Fostex D2424LV - 3 years old, used quite a bit - zero $$$ in maint.
Fostex E-16s - 20 years old - Heads lapped, need alignment tape, need tape to record all the time - Lapping = $475, alignment tape = $135, align 2-3 times/year - plenty of time = $$$
MCI JH24 2" - 26 years old - heads lapped = $800, alignment tape = $575, needs alignment 2-3 times/week (or every session depending on portability of project). Tape = $275/reel.
Cost of digital in my studio = 0 (if customer does not want their own HD)
Cost of Analog in my studio = Tape (from $65-$275/reel), maint.such as aligning, cleaning, waiting for rewind, cues, etc.
So, the sound of these two formats, if you have decent comparable equipment, is about the same as it gets. The cost (overall) of analog tape equipment is much higher (due to the age of the machines and maint. issues).
Now, if you do little time in a HR environment, both can serve you well. The only hassle is when a tape machine breaks down, the majority of the owners have no idea how to fix it. Down is down. The DAW is mainly a computer hardware thing and most all can be solved with cheap replacement stuff found at Comp USA. The one you pick is dependent on what hassle you are willing to accept. Analog machines are only available on the second hand market and you can't just buy one now and expect it to actually work. It is a gamble if you don't have substantial knowledge in this area. You may buy a machine and never get it working right, if at all.
So, what you want and when you want it dictates which format you go with.