All TI bikes are not flexy. There are many strong racing Ti frames that are as quick and stiff as any other out there. Ti is just another material that makes a good frame. I had a 2005 Vortex that was compliant and comfortable vertically but stiff as my Cannondale when you stood on it. Today I ride carbon, I am a bike junkie and will allways be switching around.

Look at the Tour photos 98-2003 or later. Mavic support bikes were allways Litespeed Vortex, today I believe they are Scott CR-1. Lance rode a vortex as his time trial bike in the Tour on two separate occasions. They were painted and badged as Treks. Those years, several other riders substituted the litespeed for their brand and had it painted to look like their sponsors. Look at the photos, especially the thin, shaped seat stays and chain stays. You will see the difference from the other team bikes. If you look at videos/photos of the tours, check the top riders bikes against the teams, it'll blow your mind.

Technology makes for great frames when using all kinds of materials. The sizing and feel to each rider is the most important factor. I like different bikes for different reasons. Ride different bikes and find your favorite.