I don't know how many of talkSPORT's commentaries are being done off-tube (I imagine a fair number of them are), but on a general note I've always felt it was ridiculous that they have consistently received criticism for covering some games at World Cups and European Championships - usually just a handful of mostly group games that don't involve any of the home nations - off-tube.
I now feel the same way about any criticism the BBC are receiving for covering a similar number of games off-tube (I wouldn't be surprised if nowadays at tournaments you are talking about both stations covering roughly the same amount of matches in this way). If anything, given how the Beeb's finances are more closely monitored these days, in retrospect it looks quite profligate how they would send a three person commentary team plus reporters and producers to pretty much every game of non-European World Cups in Japan/Korea 2002 and South Africa 2006.
talkSPORT and BBC Radio 5 Live are probably the only two radio broadcasters anywhere in the world that are covering every game from the European Championship live across their primary and sister stations (I eagerly stand to be corrected!). In contrast, I believe the major radio football broadcasters in countries such as France, Germany, Italy, Spain and Portugal typically only cover games involving their national team and perhaps one of two other major games, usually from the business end of the tournament. Even for World Cups, in the USA I think ESPN Radio produces commentaries on most/all matches - but that vast majority of these are broadcast off-tube, a far greater amount than those covered in this way by either British station.
What's more, prior to the advent of talkSPORT in time for Euro 2000, even in Britain far fewer matches than every non-clashing game at a World Cup or European Championship would be covered in the form of a live commentary by BBC Radio or the Capital Gold network. It was only really the challenge posed by talkSPORT, coupled with the launch of 5 Live Sports Extra, that prompted the BBC to shift into covering (almost) every game as they do now.
For all the complaints about off-tubing, if you look at the wider picture and make a fair assessment, you surely would have to conclude that British radio-listening football fans have never had it so good, especially compared to their continental European counterparts. I can live with an off-tube commentary as long as the commentators are good at their jobs, especially within the context of a 51-game tournament played outside UK shores that requires considerable expenditure to broadcast in full. We as British based radio listeners are very fortunate to be able to turn on not one but two national radio stations that are providing commentary on every game from Euro 2016.
Also, I have absolutely no problem with talkSPORT not signposting that some of their commentary teams are not working on-site. None of their TV counterparts who regularly cover games off-tube mention that they are working in this way and it must be said that this isn't something that viewers who comment on forums seem to expect of them. So why is radio as a medium treated differently?