... that the TH/s and the power consumption are exactly what they say they will be. This is probably not the case, correct?
Yes, except that depending on your luck, your gear could do a bit more or less, but the variance is too little and thus we can ignore it.
... that my power is 14 cents (USD) (which I'm learning is a lousy rate at the highest consumption tier, where an ASIC would certainly land me)...
It is pretty high.
... that the ASIC will run 2 years before it dies (which I'm told is possible)...
Here comes the problem, or at least a part of it, technical and physical wise with all economics ignored, there is NOTHING that guarantees a miner to run that long, while it's possible - it isn't an average by any means, so it's very unrealistic to expect that your mining gear will run at full speed for two years, there is no perfect way of estimating this, but the safest approach would be that your gear will run at no extra expenses as long as it's under warranty, after that it can either die on you, lose a hash board or a PSU and thus requires more expenses that would mess the whole rainbow scenario that you drew.
In fact, even when it's under warranty, you will lose time, from opening a repair ticket to actually receiving the gear back, a few months can pass by.
I know some people will argue that taking the 6 months warranty period as the max free-expense period is way too conservative, but this is really the only rational way I can think of, remember that you are dealing with mining gears that are made in China with little to no regulations or quality control, many of us received DOA gears, many of us had gears that died 1 week later, thinking that you will be super lucky with a mining gear that will run for 2 years troubles-free is simply betting against the odds and that is no good for business.
... and for this exercise I'm ignoring the actual price of BTC, and just focusing on how MUCH coin can be mined for X dollars...
Perfect, that's how it should be IMO.
... spreading the cost of the equipment over 2 years...
I don't want to milk this all over again, so refer to the previous part, also check my topic regarding my S9ks that came DOA, also my posts regarding Chinese miners having hundreds of dead gears after running them for a very short period of time, look around and you will see that 2 years is just isn't likely even thought it's possible.
So let's say I could actually buy an S19 PRO for 2684.00 and let's pretend the shipping is free and no trump tax, because I don't know those dollar amounts.
This is another major issue, you can't get S19 pro for $2684 not while profit is looking this great, S19 pro is $4500 in China, and it's not ready to ship, you got to wait till January (assuming bitmain sends those gears anyway), so let's just assume you can avoid tax by getting it from Malaysia and shipping is free, so re-do the math with $4500.
The calculator says that machine can crunch out 0.2625 BTC per year, at a power cost of $3863.16 per year. So double both of those numbers for a 2 year total:
= 0.525 BTC mined in 2 years, Equpment cost of $2684, power cost of $7971.60. So my costs are $10655.6, to generate just over a half a bit coin, means (not counting any auxiliary expenses ) is about $20,296.38 per BTC. And it took two perfect, no interrupted years to get there. Am I doing this math right?
I have not checked the math, but I would trust that you know how to use a simple online calculator like whatmine.com and that you entered the right power rate, the numbers don't look too far-stretched anyway, so the math seems correct, but the logic is off by a bit, allow me to take you the future and back with this chart.
This is the difficulty chart, I want to imagine that you came here, asking this question exactly two years ago (based on your 2 years assumptions), so that would be 11-12-2018.
The difficulty was 5.6T, at the time the S15 just came out and the price of Bitcoin was about $4000 and the S15 went for about $1500 which was 0.37 bitcoin back then, if you run the math back then it would give you 0.00064 daily or 0.467
BTC in two years, or 0.1 profit (27% profit on top of your investment), but guess what? non of that shit would have happened because the difficulty grew by 250%, so while it made 0.00064
BTC daily back in Dec 2018, it only made 0.00028
BTC in Dec 2019 when diff was 12.8T (-56.25% drop) and it will only make 0.00019
BTC daily in Dec 2020.
Remember, this assumes that it did indeed run perfectly for 2 years, which is unlikely, oh and by the way, those figures didn't include any power bill, just a 4% pool fee, so when you add the power cost to it, 90% of people who paid 0.37
BTC for an S15 did not make 0.37
BTC as of today.
Looking into the future when it's 2022, this chart can only be looking similar, a guy who buys S19 pro for 4.5k does the math of 19T difficulty, only to realize that difficulty has gone up exponentially and his S19 pro didn't actually mine for 2 years.
To be successful in mining you need:
1- Have a very low power rate.
2- Buy the right gear at the right price and time.
You don't have a cheap power rate, and as of now, Bitcoin mining is tempting, the demand on mining gears is pretty high, the supply on the other hand is low, it's just about the worst time to be investing in bitcoin mining, but that's just my opinion and own analysis that could turn out to be wrong 2 years from now, you can bet against it, and I will have to wish you a lot of luck because you will really need it.