Sorry, I think that is a slightly simplistic and, possibly, unfair view of what happened...
First, how do we know that trains 2 and 3 (and 4 and 5, possibly) weren't already in the tunnel when the first one broke down? (Particularly given 9053 and 9055 left 30 mins apart, a journey through the tunnel takes approx 30 mins, I don't know the stopping patterns of the 2 trains, nor if either were late, held up on the route, etc so it is perfectly feasible for one to have entered just before the first one broke down.) The tunnel, as you state, could possibly take 10 times this number of trains, and until 1 breaks down, there is no reason to stop trains entering.
You complain the tunnel only had 2 rescue locos available, and sound surprised. The East Coast Main Line, I understand, is approx 500 miles in length from London to Edinburgh and has 4 rescue locos available. The tunnel is just 31 miles long, and has 2. There's only 2 tracks under the channel, so how does having more trains help? Maybe you could argue 4 is more suitable (2 working from each end of the tunnel, 1 per line). Also, the more rescue locos you have sat idle the more you pay on maintenance and the more stand-by drivers you have to pay; a cost which is passed onto the customer. There is a case here of having to balance risk with cost, and given how rarely more than 1 rescue train, let alone 2, has been needed I think the balance is about right.
"We know that there is a cab signalling system in the tunnel which is used to give information directly to train drivers on a display." Indeed... But if you read up on the system on your wonderful source, Wikipedia, I think you will find it only displays speed instructions. Sadly, the cab signalling system isn't a free-form text screen (can you imagine what the drivers and signallers may spend all day doing!) on which drivers can be informed of delays, etc. So your comment about "the communications route was there for the train staff to be kept informed about what was going" is not accurate in this form. I would hope that there is in-cab radio for this sort of thing, but if the electrics have been shorted out there is a chance this would not be working (I would hope there is a battery backup, but even that will have limited capacity and may be prone to the same shorting).
There is probably a good reason why doors must remain closed in the tunnel (or anywhere else for that matter). What happens when someone opens the door and gets off? They could get left if the train suddenly starts to move, fall off the walkway under the train, etc. This is a safety issue and I think to criticise it is just plain wrong.
On the matter of emergency food and drink... Well do you really expect them to have an extra supply of food and drink just in case something goes wrong? For a quarter-mile long Eurostar just think how much space this would take up. And what do you do with that food? Keep it there until it goes off, throw it away and replace it? Just think of the waste and the cost!
Don't get me wrong... I'm not saying the companies invovled are totally free of blame. Procedures do need to be reviewed in light of what went on. Communications in particular need to be looked at.
Why do we need a public inquiry? Things go wrong all the time. I would hope that the relevant safety boards do their investigations and that recommendations are made and implemented. But do we call for a public inquiry every time something like this goes wrong? There have been worse incidents than this where people have lost lives, yet the standard investigations are carried out, recommendations made and implemented and life goes on.
This is, sadly, not a perfect world. Things will always go wrong. All we can do is learn from our mistakes to try and make sure they don't go wrong again (at least not in the same way!)