Yes
Especially in the UK where road racing is still very much a minority sport.A massive spectator turnout and big boost in bike sales could be expected with continued GB success and a UK Grand Depart.
There is an awful lot of money and business involved of course.
Then there are things like the "SKY rides" which are organised rides often for beginners or family groups all riding round in dayglo SKY bibs,nice advertising bonus and more new bike sales of course.
http://www.goskyride.com/
Much of the interest would fade quickly if some Spanish or Italian guy wins the tour as the UK at large does not have that basic interest in the sport.