Hmm. I've been an endurance athlete for 25 years (mountain biking), and had the exact opposite experience. When I switched from smoking to vaping, almost straight away I noticed my breathing improved, I was less likely to "run out of breath". But my situation isn't the same as yours: I had only been smoking a few years, and had done the endurance sport much longer. Perhaps our lung condition is not the same and our bodies work differently. Theres many reasons why our experience could be different.
Remember that smoking is really just a crude vaporizer. Cannabanoids inside the cherry are destroyed by the high temperatures. Smoke doesn't get you high, the smoke is only a vehicle for cannabanoids to enter your lungs. Those cannabanoids that survive combustion and make it into your body, are coming from AROUND the cherry, not from the combustion zone.
Hot smoke leaving the combustion zone passes through green material, causing oils to become airborne (vaping, in other words). Radiant heat from the cherry warms the surrounding green material, causing the oils to become airborne, which are mixed with the smoke and carried to your lungs (again, vaping). The temperature of the smoke varies, depending on distance from cherry, but there is a section within vaporization range. When you smoke, you're getting vapor AND smoke mixed together, not just pure smoke. To think that smoking doesn't produce vapor, shows a lack of understanding of the physics involved.
To illustrate this, think about those guys who run their vapes HOT and often combust, and some users really enjoy that middle ground between vaping and smoking. I know a guy who heats up a quartz rod, and uses it to vape AND smoke the same bowl. First few hits are vapor, and then it changes to smoke. Surely you don't believe the vapor just suddenly stops at the exact moment that combustion happens? With all due respect, thats not how it works.
It's totally OK if you prefer smoking to vaping. But I think you're mistaken when it comes to interpreting your bodies reaction.