I suppose the big question will be where do you put these lounges and how much is it going to cost?
Rent for space in those stations would not be cheap whilst there would also be additional staffing costs as you would need at least a couple of staff to run each lounge (Presumably one serving and one prepping drinks/food) although the check-in duties could possibly be passed onto the staff here rather than the crew which would solve some of the problems the crew are having to deal with.
Logistically it could end up costing them more that they make by some distance.
Also if this were a proper hotel and I was up to two hours late getting access to my room I'd probably be getting offered comp drinks/snacks whilst waiting in the bar area which would be additional cost. There has been reports of a CS manager standing tapping away at the PDQ with the company credit card at Upper Crust at Euston but this was in the early days of the new stock. If there were dedicated lounges there would be an expectation for a bit of "Customer service" to be happening in the event of delays. I'd go as far as to say it actually suits Serco to have passengers milling around Euston Concourse as it costs them less. I've heard of hotels at sports grounds comping full nights if there have been problems with accessing rooms after evening events
With the fares being charged and the well heeled being targeted it's only a matter of time until they are taken to task for the way they are handling the current problems.
And here in lies the problem Serco are charging premium and super premium prices for the offer when the service doesn't match up, at the current pricing levels there should IMHO be a lounge available at all the principle stations served open until boarding commences. They can only go on for so long with current problems before the passengers desert them, having a £400 "caledonian double" boarding a couple of hours late so loosing 1hr+ of sleep time really isn't a good way to achieve passenger satisfaction. As you point out traditional hotels would comp the room for that level of interruption or at the very least comp extras such a snacks, drink etc. Passengers for the doubles and club rooms are realistically making a choice between day train + hotel or flight + hotel vs CS.