Why no build in hood like 300 4.0 or 400 5.6?

Hi,

since I have seen the 300 L 4.0 and the 400 L 5.6 i started to wonder why canon does not build more lenses with hoods attached?

There are many lenses wich have a longer size to allow this design wich I abolutely love. Just thinking about:
70-200L 4.0 and 2.8
200L 2.8
70-300
55-250 EFS
100-400 L
100 L Makro
135L

Wouldn t THIS be great?

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allways look on the bright side of live!