Get the cameras out, because you won't often hear me say this, but I agree with Martyn.
The killer point, which I notice Gareth doesn't address, is that Manchester's catchment area extends in all directions. Liverpool's extends (to simplify things, effectively) only eastwards - which then overlaps with the catchment area of Manchester.
Liverpool is poor. There's no getting around that. No amount of regeneration or investment in huge, pointless projects is going to change that. Why do I work in Manchester but live in Liverpool? Is it because of the large, extravagant parks? The vibrant nightlife? The friendly people? No. It's because it's cheap. I can afford a two bedroom house here for less than a studio flat would cost in Manchester. A pint costs £1.39 at my local.
Liverpool, along with most places further south, such as in the Midlands, gain the benefits of HS2 via the freed-up capacity on the classic lines.
The biggest failing of Liverpool's rail connections is that we have a train service to Manchester which takes longer than it did in the days of steam. Worry about the basics before we start anything else.
Oh god, where to start with this...
Okay, catchment area: you say Liverpool's only catchement is eastwards. To me, this insinuates that Liverpool is surrounded by sea on three sides. I thought a simple map here would blow this one out the water but I've added arrows, red ones at that, to emphasise the point, to be safe...
Yes, Liverpool is near the sea if that's what you're trying to say. So is San Francisco. So is Barcelona. So is Melbourne. FFS, so is Newcastle-upon-Tyne! What's your point here exactly? The reason I didn't mention 'catchment' is because it's pretty much a non-argument that I assumed didn't need addressing.
As for the next paragraph: yes, Liverpool is relatively poor. But guess what, [drum roll] so is Manchester, by most realistic indicators. It has similar levels of deprivation, equally dire projections on life expectancy, heart disease rate etc and has more crime. Once you take away the Northern Powerhouse rhetoric, it's not that special, on the grander scale of things. It's just another northern town that, apart from the state trinkets it gets for being Whitehall's regional administrative centre for the North/North West, will never reach its potential so long as it remains in such a ridiculously centralised and London-centric state. Pretty much the same boat every other large UK city is in.
Forgive me, if I take the rest of what you say with a pinch of salt. I'm not accusing you of lying, as no doubt you're a man of integrity but I'm struggling with the concept that you couldn't find anywhere closer to Manchester where you could get a cheaper house or pint of beer. Considering you're not exactly a man of culture, by your own admission, I'm surprised you had to go this far out and that various actual Mancunian satellite towns, if not more the crummy areas of Manchester itself, failed to yield options. Again, pinch of salt with your comparison of a homely two-up-to-down in Liverpool to a trendy studio apartment in Manchester. You couldn't afford a trendy studio compartment in Manchester so just gave up and settled for a two-up-two-down in Liverpool? It's an apples and oranges statement that we can easily reverse:
here's a studio flat in Liverpool that's over four times more expensive than
this two bedroom house in Manchester.
As for the pint of beer, I'd love to know where your local is. Mine's certainly nowhere near that cheap and I'm not in a particularly posh area. Even so, I'm sure your 70 mile daily commute more than wipes out the discount.
Liverpool needs to be well-connected to the rest of the country, just like every other major city, not just to Manchester. Just because that's the one that most benefits you personally doesn't make all the others unimportant. Liverpool's not going to become a Greater Mancunian satellite town, as much as you and a rather notable minority of the train enthusiast community seem to want it to be. Not only is it not desirable, it's also impractical. Liverpool's too large and not quite close enough. Either that or Manchester isn't large enough and needs to, at least, treble in size. Not going to happen. What Liverpool faces, if this marginalisation continues, is a withering, possibly to nothing. People in the 1.5-2m metropolitan area are not going to commute en masse to Manchester. Even considering the stress on the transport network (and the environment for that matter) Manchester could never support the jobs. They'll simply be forced to leave; some going to the actual Manchester area but most going to the South East no doubt.