I follow your thinking entirely, but the character of the underlying industry in Europe is so different to that of the US that the commercial constraints and imperatives are similarly divergent.

Consider this: An American Airlines passenger in Miami is booked to Seattle via Chicago. Chicago is forecast severe weather and a travel waiver is issued. The passenger is either automatically rebooked, or offered the opportunity to rebook themselves, via Dallas instead. Or New York. Or a couple of other transit points. All on American.

Meanwhile, a British Airways passenger in Madrid is booked to Stockholm via London. London closes - probably temporarily and relatively unexpectedly, as it's subject to far more varied and unpredictable maritime weather conditions than continental Chicago. There is no other British Airways routing available.

There are also likely to be a far higher proportion of passengers on the exMAD flight connecting to a longhaul intercontinental out of LON, than there will be exMIA going to ORD. Not unconnectedly, there may be transit or entry visa issues, ESTA issues, even Schengen issues within Europe if an overnight transit somewhere down the line becomes necessary.

Fundamentally then, European aviation tends to work with lots of national carriers operating linear connecting routes through one hub, with maximum point-to-point frequencies on the busiest routes of a perhaps 8 daily, connecting to longhauls that may not even have once daily operation. Only LH really has two hubs in MUC and FRA, and arguably AFKL with CDG and AMS. The problem with the latter case is that when CDG goes down with weather, AMS usually already has too.

In the US though, there is a 'web' network, with sometimes 16 or 20 daily frequencies between each node, fewer carriers and therefore more options for rebooking at limited risk to the original carrier.

To mimic that in Europe, Lufthansa would realistically have to allow passengers on its affected flights to unilaterally rebook themselves on to Air France or British Airways to get around the hub that's closed. Clearly, that's not going to happen - the logistics and costs would be incredible.

And, whilst a huge continental weather front passing over the Great Lakes can fairly reliably be predicted to take x hours to pass, allowing airlines to make educated longer term guesses about rescheduling, it tends to be sudden 15-minute snowfalls that send things spiralling out of control in Paris, Amsterdam, London and Frankfurt.

Of all the European carriers, Lufthansa would in theory be best-placed to introduce that level of passenger re-booking flexibility, given its ownership of BD, LX, OS, SN etc and its own two hubs. However, if you look at the respective route maps you'll see that a good number of the network outstations are still only served by one of the LH group airlines, or frequencies are very low. So, if your 17:10 LH exNCL to DUS is cancelled because DUS is closed, then the only other option is SN (in group). Unfortunately, the last BRU went at 16.30 and, as BRU is only 125 miles from DUS, on the same latitude, there's a more than evens chance that BRU will be suffering irrops too.

So, as much as the concept of a travel waiver system is appealing and seems to work fairly well in the US, it seems exceptionally unlikely that it could practically be applied to Europe without putting everyone's ticket costs up enormously. Indeed, it's not even a completely magic bullet in the US: if your destination is the waivered airport or you do have a complicated onward connection then you're in no better position than you are with ba.com - which is notably good at allowing rebookings when irrops are confirmed.

Of course, if you still want to effectively issue your own travel waiver outside of the US, then you can simply buy a fully-endorsable IATA ticket, transfer it to an operating carrier whose routing is within the MPM and fly your way around the problem. At a price.