tpr, I respectfully disagree.
The Scotch and Berlin became more popular due to better theory and re-evaluation of the openings. In essence, we discovered that they are actually pretty good.
The Italian is a sort of similar case. When it's played today by GMs, it's usually d3 lines that look like a closed Ruy, not classical Moeller attack stuff and the like.
The London, Colle, and Trompowsky don't seem to offer more than equality. (If you have an argument that this is not the case, I am genuinely interested in hearing it!) For example, the lichess database has black outscoring white after 1.d4 d5 2.Nf3 Nf6 3.Bf4 c5, and the Stockfish evaluation at 0. This is horrible. If you're going to go through the trouble of booking up, why learn something that tosses the first move advantage away after 3 moves?
The Alekhine and Pirc are objectively not that great, and there's a reason they're mostly used as secondary defenses or surprise weapons. I can pull some critical lines from e.g. the Alekhine from the chesspub forums if you doubt this. Further, they're poor choices for a middling player online because of their hypermodern nature. They require some fancy footwork and theoretical knowledge to play accurately and not get rolled. (This last point is perhaps debatable, but it was the opinion of the late NM Mark Morss, who advocated more classical and open openings for developing players. He managed to produce a national high school champion, Abby Marshall, so I take his thoughts seriously.)
So again, if you're a club player and have little study time, why not just pick a single good opening as white and one response each to e4 and d4? Why intentionally learn bad openings?
Greg Shahade has a nice list of top quality openings here:
http://www.uschess.org/content/view/11634/675"If you really want you can play the Alekhine’s Defense every game, or the London system for white, though I’d never recommend these to any of my students as a primary opening choice."
Also:
"You can play stuff that’s completely unsound because the large majority of sub 2000 players won’t be able to take advantage of your dubious opening choices. Understand that if your goals change, you may need to learn something new according to your new ambitions. If this is only a short term goal, and at some point in the future you’d like to become even stronger, you will be cheating yourself by not immediately learning more serious variations."
I think we all want to become stronger...