Not true. I saw Hoggard get above 80-odd mph many times during the Ashes. Conversely, I noticed Bracken was generally high 120's and on occasions, low 130's in the WI Tests. Very rarely did I see him get above 135km/h. I'd say that, on average, Hoggard and Bracken would be largely exactly the same pace. Bracken, in fact, seems to be as slow with the ball as he's ever been. Whether that's deliberate or not, I can't say.
Anyway it's all academic; when I've face guys who were bowling at 130km/h and others who were around 140km/h, the difference was bugger-all at the business-end. It's been a while so someone currently playing high-level cricket could confirm this; Jack?