Your arguments like many of your posts, are a bit all over the place.
"Air travel run for business class?" Never noticed any class division on Ryanair on routes to the sun, must've missed that.
I fail to see why curtains are the be all and end all for business class train travel. I have used laptops on ICRs, with a handy plug socket at every seat (something missing on older coaching stock) without the need for a curtain.
Comfort, the Mark IIIs were very good but were tired. Economic decision to get new trains while the money is there over expensive refurbishment made sense (this is where Kieran's point about new seats came into it that you happily dismissed to suit your agenda once again). Coaching stock needed shunting, 201s and 071s thirsty. mark IIs clapped out. I personally find the ICRs very good. Noisier? Of course, but it's not that noticeable to me and it hasn't affected passenger numbers.
Most railway companies across the water and beyond have stripped back their catering as much as possible in recent years, including Virgin and my once beloved GNER and its successors. Good food on trains is like that on planes, a thing of the past.
The M50 station idea is surreal to me. If you can show me a successful railway station on a motorway I will gladly read up on it. Heustons big problem is that it's too far outside the city centre. So why build something further away that's even more inconvenient? If I was a person travelling to Dublin city centre on business and was turfed out in cherry orchard I'd be livid. The opening of the Phoenix park tunnel next year to southern services to grand canal dock will be fantastic and I'd be happy to bet that it will increase travel numbers on IE.
If you want people to switch from cars to the train for such journies it needs to be much faster, affordable and convenient than driving. Hence the calls for better line speeds and the calling at more city centre based stations. This in turn can get many people out of anti social, gas guzzling nonsensical vehicles unsuited to the city centre. IE is also more affordable than British train travel under the private model.
Outside profitable commuter and the more established intercity routes, the idea is to provide public service for the good of the citizens of the country. Will these lines make money? No, but that's not necessarily the point
Just my two cents.