I'm 59 years old and I've been doing tri since it first became an organized sport back in the 80s. But...I've never had more than an aluminum Cannondale road bike set up for tri with clip-on bars/brakes, and a seatpost that provide a more tri-friendly angle. I've always kept it set up for tri, and used it for racing only...and would train on my other road bikes. So...my opinion may not be that valuable to you. In the past 15 or so years I could afford an expensive tri-specific bike if I really wanted/needed one...but why? As a 'weekend warrior' who am I racing against? What am I trying to accomplish? Regardless of whatever bike I could be on...I'm not going to be vying for 1st place overall. Nor even in the overall standings. Occasionally I would snatch an age group award. And I would just chuckle when I'd see others in my age-group on very expensive tri-specific bikes...finishing well behind me. So...(IMO) if you're seeking to move up in the overall standings, and you think that the expensive, tri-specific bike can do that for you...do it! Or, maybe you just like the idea and feel of a more specialized, technical bike. That's OK too. But...if the race is just in your head, and you're only racing yourself and trying to beat your
PR...stay with the old bike and relish the times you beat those expensive bikes.
Dan