In general, I want to point out that I am not frustrated and that this is not a reflection of my own personal management or hiring style. I was just trying to explain the context of why you might see overly specific job requirements in a job posting. I will however add specific comments to the one area of your response that I think I can add value to.

This is easy to say, a PITA to do:
i) Use LinkedIn to meet people. Do not be afraid to contact the recruiter or hiring manager directly. You can use in mail or ask for a reference. I always respond to people as long as they are reasonably polite and appear to have a clue. Someone who has the initiative and intelligence to put together a sensible introductory email has already passed the first hiring test in my opinion.
ii) Tell your friends you are interested in working at company X. Ask them if they know anyone at Company X. Then make them introduce you. Once you know a single person at the company, you can use that connection to basically meet the entire company. But remember, they are doing you a favor so treat them well and be sure to reciprocate in some way.
iii) Go to industry events. If you want to work at a company that builds content management software, then try to go to events about content management, DAMS, CDNs, etc. Who cares if the event is boring. You are going to meet people. If you meet a single person at each event you attend which leads to a follow up interaction (like a coffee/drink/email exchange) then you have succeeded.
iv) Develop a specialty (or 3). In doing this, you will meet people who work in the field. Instant network. And by specialty, I don't mean a PHd or 10 years of experience. A smallish project or two at work or a hobby project on the side is often enough. The point for you isn't to duplicate the Apollo project by yourself, the point is to do something interesting that allows you to meet people. This will also make you a better candidate. I love hiring software generalists that I can assign to any task but who have specific knowledge about the problems I will need to solve over the next 12 months.
v) When you read something interesting online, send a note thanking that person.

I have personally gotten jobs or hired people through all of these methods. I have a ton more ideas (including cold calling) but I know for sure that these ways can work.

For what its worth, I agree with you about job fairs. I never go to them when I am unemployed. Instead I am out having beers or a coffee.

Honestly, I have a fair amount of luck with recruiters too. I have picked a couple that I really like and have developed a personal relationship with. I also go to them and they often have good opportunities or ideas. It doesn't hurt that I occasionally meet them for beers or coffee when I am not looking for work or actively hiring

Networks take a lot of work to build and it takes time. So start now :)

I have hired dozens of software engineers over the years. Most of the time I get approved to hire a new staff member because i) the project is late or ii) somebody critical has just left and the project is at risk of being late or iii) its a new project that I have to quickly staff or it will be late.

I usually assume that it will take 4 to 12 weeks to find an appropriately qualified engineer, then 2 weeks for said engineer to give notice at his/her current job and then 2 months to ramp up on our existing product stack. During these 14 to 22 weeks, this new resource is either not providing any benefit to the project or is actually slowing the project down (ie during interview phase and during ramp up phase). This is always bad news and no VP ever wants to hear that velocity in his/her pet project cannot be improved for at least 14 weeks. Now imagine that I have to add another 1 to 2 months of slowed velocity while this new engineer upgrades his or her skillset (or occasionally downgrades to an earlier version). Ugh.

That is why there is a huge preference for people that know the exact tool chain and software stack that the project is already running. Time.

However, I (and most managers) personally don't care if you have some specific sub release of SomeLanguage++ 5 (for example). But you ought to have coded SomeLanguage++ professionally and well within the last few years on some significant project where you can point to some kind of value that you added. Your 2 months of SomeLanguage++ 3 experience from 2001 is not interesting to me.

At large companies, the HR department may very well screen on precise versions of a software stack. Solution: use google to figure out what is significant about that release (if anything) and how it differs from your knowledge about the stack and then add that specific version of that software to your resume. The dev manager isn't going to care that you only used PHP 5.4.3 and not PHP 5.3.25.

Even better solution (assuming its not the gov't or some massive corp): Find out who the hiring manager is and somehow get introduced to them. The devil you know. I totally prefer to hire people I have met that are known to people in my network. Why? Because I trust my network. I do not trust the Internet.

Either way, the manager will want you to be able to prove in the interview that:

a)You are a good person who is reliable, easy to work with, dependable and can hit the ground running and get me out of the hole that some sales guy dug for me
b) You have specific knowledge about the technologies that you claim to know
c) You have work experience to back up your claims
d) You have the skills and capabilities to succeed as an engineer in my organization
e) Ideally that you can do more than what is minimally required for the job

I specifically recommend that you do not complain about the job posting in the interview. ;) Actually, don't complain about anything in the interview.