Equipment Price Points

Until you reach the elite levels, the engine will trump technology every time.

Put me on a Cervelo P5 and Macca on a mountain bike.... I'm pretty sure that he's still going to kick my butt over 112 miles.

The average age grouper is not going to see much of a performance difference between a 1500-3000 dollar bike compared to a 5 to 10,000 dollar bike.  However, at that top level, tiny differences in equipment can make a huge change.  Consider Crowie's improvement on the bike from 2010 to 2011, when he switched from Orbea to Specialized. While training more than likely had some influence, equipment definitely helped.

I think this statement needs to be turned around.  If those bikes were $3,000 in 1989, the equivalent in today's dollars would be much higher.

So, I would say that you get a much more advanced bike for the same inflation-adjusted dollar today than you could get back then.  How much does that help your actual time?  Probably a small, but measurable amount.

A $700 bike with clip on aerobars is fast enough to win the Kona World Championship if the right rider is on it. 

Chrissie Wellington could won many races on a very used road bike + aerobars (read her book - it was barely functional at times since she couldn't afford to fix it up), and she definitely could have won at least one if not more of her world titles on that same bike, given that she won by like 5+ minutes even after a flat that cost her even more time. 

You pay a massive premium for teensy bike performance, especially on frames. My $700 entry-level roadbike is probably 99.9% as fast as a $10,000 road bike, for example, and just shifts more slowly due to the Sora components.

Also, one must consider that the $10,000 bikes usually have electronic shifting which doesn't really affect speed.

My point being that one can spend thousands of dollars more on a bike without having increased speed as the motivation.

I don't know about that. 

From what I have read you can shift from the hoods or the bars, you can shift while standing going up a hill without dropping a chain.... and you shift accurately every time.  I think that might save some significant time on the right course.

Not that I disagree with the general point.

I'd say that the law of diminishing returns applies heartily to Tri bikes. 

As with all technology, materials and construction improve and always come down in price over time.  Those bikes would probably be worth $50 today.  Think about a $3,000 computer in '89 and what it would cost today.  Plus, I think today pros ride $10K bikes or more, $3,000 is probably the average age grouper bike these days.  

Di2 is worth every penny!  but that's for another thread.   

But yeah- your body position makes more of a difference than how aero your frame is.  In fact - the bike frame (other than fit) probably has the least to do with performance.  An aero helmet that you can pick up for $80 will give you the same benefit as a $2000 set of wheels.  Problem is- wheels are cool.  Aero helmets (outside of races) are not.  These fancy bikes are toys... but fall in love with one, save your pennies and buy it.  you'll ride it more- and consequently get faster.