If you're travelling just from Lime Street to Euston then I agree. Its a pretty good service to be honest and I've used it plenty before, but I still think its expensive. An off peak return on the day is about £75. Of course most people aren't just going from Lime St to Euston. Once you've factored in the time and money it takes to travel from home to Limey and then from Euston to wherever you're going there's very little in it. Of course if there's two or more of you there's no doubt car is cheaper.
I live in Birkenhead and that journey time I quoted included walking to Birkenhead Central, getting the train into Lime Street, waiting for the London service and then on to London. I've managed the journey at anything from £7 one way to £70-odd, if I had a family, of course the car would come in both more convenient and cheaper.
As a business traveller the route is fantastic, if First fuck that up, then they can kiss their projections goodbye and they'll be handing the franchise back. Ah wait, didn't the minister say that the previous franchise problems (East Coast Line?) where First walked away, were down the the Labour Govt (here we go again) allowing a 'walk away' clause? I assume, therefore, there is no such clause in this new franchise, hoorah, we are saved.
Someone mentioned an airline service to London? I'm afraid that has been tried and it failed (from Liverpool I think it was VLM?).