Reddit mentions of Performance Tool W80527 25 Blade Metric Feeler Gauge

You're right that automation, when done right, is generally more reliable and desirable due to precise repeatability. But the issue here is that the current ABL sensors/systems, from an engineering perspective, are not done right.

A properly engineered auto bed leveling system would actually turn the screws and physically level the bed. But the existing ABL sensors don't do that. They take readings and compute in firmware the orientation of the bed, and cause the Z axis to constantly adjust during the length of the print to compensate. This method opens the door to other issues that are unique to an ABL-enabled system:

• The sensors themselves can be thrown off by something as simple as a change in humidity levels, and their accuracy is hindered by a glass bed if your printer uses one or you wanted to try one.
  
• The microsteps required of the Z axis stepper(s) to perform the required very fine movements are not as stable as full steps, which could introduce noise in your Z layers.
  
• Even when they work, with a bed that is actually unlevel your models will be provably skewed. The sensor doesn't magically build up a couple of uneven first layers to build up a truly level base for the model to print on top of for the rest of the model's height. It just runs the same extruding G code as computed by your slicer, with skewed Z values to match the skew of the unlevel build plate. The more off-level your build plate is in reality, the more skew your completely printed model will have on all layers. To mitigate this effect you still need to manually get the bed into a generally level state before starting. There's no getting away from it.
  
  I don't think I have any "superstar talent", as you put it. I just use a feeler gauge to set a known distance from the nozzle to the bed in one corner, and zero out a digital dial gauge that I have mounted to my extruder carriage during leveling. Then I just move the extruder head around each corner of the build plate, adjusting the bed screws until the dial gauge reads within +/- 0.01mm (the tolerance of the gauge itself) of zero on each corner. It is a perfectly repeatable process, and takes no more than 2-3 minutes to get a perfectly level bed. (Edit: This is my method using those tools because I'm a perfectionist, but good results can also be had with the tried-and-true and dirt-cheap "paper between nozzle and bed" method). On a properly rigid system with good compression on the bed leveling springs, I only have to level once a month at most...and that's usually when I've changed something in the system that invalidates my previous leveling anyways.
  
  All this to say...I just believe your initial post was overly hyperbolic. It sounds like you had a bad experience, and if ABL worked to solve that problem for you, great! But to use your singular experience as a reason to emphatically suggest at length that someone new to the hobby should not even consider any printer that comes without ABL, especially when there are countless more people who have entered the hobby just fine without ABL? That's a bit much.