I got a Nissan Versa hatchback (used) mostly because I could easily put my bike in the back (laid down) without even taking off the front wheel --well I do ride a 15" frame. And it was also the least expensive 1 year old, still under warranty car I could find at the time. MPG about 30.
It has worked out fine so far, but on a trip with the bike, space for luggage is limited. Fortunately I travel light.
What would make a car good specifically for a triathlete?
Plenty of room, ease of loading equipment, comfortable for the drives to events, easy to clean interior, good MPG, ability to transport more than 1?
Definitely take your bike with you and try loading it in the cars you are considering. And make sure exterior racks fit easily and well.