Why would they? Perhaps in the US such services have been made available for legal reasons, but to be quite honest I see absolutely no point to it other than avid spotters F5-ing their favourite airport to see who's coming in today.
On the other hand, you should consider the security implications this has... after all, all major airports in Europe remain on the lookout for people brandishing portable surface-to-air missiles in the vincinity of their active runways. Such a system would provide people with bad intent with a means of telling when exactly a certain flight is coming in, long before it is within tower range.
To be honest I would really like such a system to be operational in Europe just as much as you, but so far we seem to be doing fairly good without one
