I'm busy at work so I'm only going to address two of those points.
Firstly, many games just assume an internet connection is present these days because there's hardly anyone out there not hooked up. BioShock connects to the internet to activate, all of Steam's games do (which now includes hundreds of non-Valve games if you hadn't notice), and in general a lot of games use it for automatic patching and such.
Nobody sees a single-player game requiring a connection as unreasonable anymore because pretty much nobody doesn't have a connection there for it to use. I really recommend you get your main computer hooked up rather than this crazy splitting thing.
As for HL1, it really isn't the most popular game at all. Counter-Strike accounts for almost all the players, and I can tell you without any hesitation whatsoever that the vast majority of those people have no interest in trying out different HL1 mods. Day of Defeat and TFC still have players, but a lot of them are bots and just like with CS most of them are just addicted to those mods and won't try anything else.
And that Paranoia shot you showed doesn't look particularly good, D3. It looks better than most HL1 graphics, but it's still noticeably inferior to the first-generation version of Source (2004). The latest generation as seen in the Orange Box has much nicer lighting, use of HDR, and generally looks better.
As I said, HL1 remains popular only with very small enthusiast communities. No mod for HL1 is really going to hit any headlines, just like Paranoia didn't. And more importantly, all these people playing newer games aren't going to go back in time and play a HL1 mod. It just isn't going happen, and I'm dumbfounded that after all we've said you still can't see this.
I'm glad you're looking into the suggestions, but please don't make excuses for your outdated mindset. Without making you paranoid or anything, we have discussed you on IRC before and the way that you're clearly throwing away your potential; indeed, some people in #mapcore have said they wish they could edit like you can and are amazed you're just doing nothing of note.
It's time to stop moaning about Steam requiring an internet connection (we all did that and forgot about it over three years ago), get everything on one gorgeously powerful PC, and start making visual magic.
I don't really want to drag this out though, and will let you have your own thoughts from this point on. All I can do is desperately urge you to accept that HL1 isn't on the radar for most gamers, it looks extremely outdated without any exceptions, and your time would be infinitely better spent working on newer engines. ![]()