I understand exactly the point of the exercise, and I was once in the boat of being uneasy about spending on photography. When I got started, I didn't even buy my Nikon D40 new because its $499 kit price was too much.
However, once I realized photography was "for me", and I started upgrading equipment, I did so with an eye toward having gear that was high quality rather than filling all needs as quickly as I could with my immediate budget. I think it's better to have quality equipment and gaps in your lens lineup than to have a "complete" set of lenses that aren't what you truly want. There is no such thing as a complete kit, anyway.
For example, I could have afforded the Nikon 35mm f/1.8 a couple of months earlier, but instead I waited and got the superior Sigma 30mm f/1.4.
I'm not saying that people should wait forever to buy the absolute best (certainly saving your money to buy a D4 and Nikon 14-24mm in three years isn't a better option than buying a D7000 and Tokina 11-16mm now, because the former means 3 years of "missed" photos in the meantime), but I think spending money "now" just because you have the money is often a poor idea when it comes to photography. You'll quickly find yourself replacing those "gap filler" items.
I agree with everything you said.
Though much of your eye for quality, depends on the level of your passion and the time you've invested.
As a drinker of quality wine, I'm often confronted by someone who says, with all honesty, that they can't tell the difference between a $20 bottle and $100 bottle.
Applied to your examples-- for many many people with a moderate interest in photography, the 35mm 1.8 will serve them almost identically to the 30mm 1.4.
To such a person, would I recommend they save and wait? Or as the 35mm 1.8 will truly serve their low light needs, I'd tell them not to bother with the more expensive lens.
To Tom Bricker... I'd say save and wait. To the poster on the board that says, "I just got a Canon T3, what lens should I buy to take dark ride pics at Disney next week?" I'd tell such person they will be really happy with the 35-1.8.
Of course, some people, myself included-- as their passion grows, their eye becomes more distinguishing, and they outgrow their lenses. For a long time, I was happy with my nifty fifty for portraits. I certainly got my $60 worth out of the lens, but it now sits in the back of a closet. As my eye has become more discerning, my passion grown, I'm much pickier about my lenses.