I'm sure some cars are already capped, ie the TT-RS is capable at 160mph and more but its capped to 160...
What about other limitations, IE the German autobahn... then the hole some countries have higher speeds due to KMH in some cases, unless they standardize all roads across europe it won't happen, plus councils and local governments will become sad due to no hefty fines from speeding tickets or speed cameras as this would drastically fall. Ie my mates 400 euro speeding ticket in Holland, now if his car could only do 70 they wouldn't make such big money.
All in all, it won't happen, just BS media.