I passed that site earlier in the year and didn't see any 373s there, just a couple of TGV PSEs waiting for the chop. I guess it's already history.....
Those photos were posted on that forum in June 2015, so unless that retired set is now parked up somewhere else, it may well be history.
....Frankly I find it amazing that a company making only £50m operating profit can blow a billion on new trains when the ones they have still have life in them....
If the 373's only had a few more years left in them, without the update, then that wasn't much remaining life at all.
A few things to consider....
Firstly, Eurostar needed extra trains to allow them to expand their range of services and routes.
Secondly, the age of the older stock and the cost of keeping it running.
Increasing age often means increasing maintenance requirements, which equals increased costs/overheads and probably reduced availability.
Do you pour more money into the update and refurb, when the economics of buying new, more up to date and probably cheaper to maintain trains, makes more sense.
Thirdly, asset value.
When a train no longer has any asset value, it can have an adverse effect on the balance sheet.
The 373's are now more than halfway through their useful life, but they will still be around for another 10 years or so.