Rooney made his first tournament appearance in 2004, Walcott made his first tournament appearance in 2012. He was a token pick in 2006 when he went to the world cup, we didn't qualify for 2008 and he was left out the squad for 2010 - which Capello has since admitted was a mistake and even Messi said was a shock.
Rooney was 18 when he went to the 2004 tournament, Walcott was 16 when he went to the world cup 2 years later.
Walcott has had massive injury problems whereas Rooney has played probably well over 90% of the games for England in the last 10 years.
And finally...Walcott has been wrongly shoved out onto the wing for his entire career since leaving Saints. On the odd occasion he has played up front in the last season or two for Arsenal, he has looked incredible and banged the goals in.
Your comparison is ludicrous.