A 1X12 system with a 12 sped 10-51 cassette would have a range of 510 percent. And the average step would be about 16 percent.
My 3X8 derailleur touring bikes have a 46/42/24 triple (half step plus granny) and I use a Sram 850 11/32 cassette. I am using bar end shifters, front friction and rear indexed. The user experience between my 3X8 system (or any 3X8 or 3X9 or 3X10 system) is quite different than the 1X12 system, the 3X8 has an extra shifter and each chainring has its own gear range. When you shift, you have to think about which shifter to engage.
For my 3X8 system, total range is 558 percent. With half step, the upper two thirds of the gears are quite nicely closely spaced and then I have a few bailout gears for the steep hills using the granny gear. Since I am rarely on my granny gear for very long, I am quite pleased with wide steps between the lowest gears and very close steps between the middle and highest gears. I did not start out with a half step setup, but changed to that about a decade after I built up my first touring bike after studying gear charts.
For my 3X8 system, the chain at Amazon is between $12 and $15 USD for a KMC X series chain, Sram 850 cassette about $20 to $25 USD. A quick google search tells me that the 1X12 cassette is roughly five times as expensive and the chain is about three times as much.
***
The reason that I am comparing the 1X12 with a Rohloff is that a Rohloff while mechanically is completely different than a derailleur bike, I would assume that riding the two bikes would give a very similar user experience. Both have one shifter from bottom up to top. The 1X12 is 12 speed and the Rohloff is 14 speed. As you are riding, when you want to change gears you reach to the shifter and you shift accordingly.
When I first bought my Rohloff, my primary complaints were the range was only 526 percent and the average step size was 13.6 percent. On both of those topics, the Rohloff wins over the 1X12, meaning that what I complained about with the Rohloff, my complaints would have been louder on the 1X12 system. The initial cost of the Rohloff is much more and the Rohloff is heavier, those are obvious disadvantages.
That 1X12 system probably has higher maintenance costs than the Rohloff, as that would not be a cheap cassette to replace. Rohloff, the maintenance costs are pretty low, but i should clarify that I bought the 250 ml oil change bottles about half a decade ago, so I have another half decade of oil on the shelf waiting to be used, the individual oil change kits are more expensive if you buy a new one each year. I probably have 3 or 4 more years left on my rear sprocket, not sure what the price is for a Rohloff sprocket but I suspect it is comparable to my 8 speed cassette in cost. Rohloff uses an inexpensive 8 speed chain and since there is no cross chaining it lasts longer than a derailleur chain.
***
Bottom line, I am happy with what I have, I have no desire to run out and buy a 1X12 system. I am fortunate that I can choose between a Rohloff bike and 3X8 derailleur bikes when i go on a bike tour, each has different characteristics and for some trips I pick one and other trips the other. My tour last summer was with the Rohloff bike, my planned (and now canceled) tour for this year was going to be on a derailleur bike.