Marginal gains? The nice boys at GCN once summed it up nicely. Apparently the Watts saved by using a lighter inner tube would have made the difference between third place and first place in a TdF stage, assuming the other riders did not have such. The cost of multiple marginal gains in your case would be about $10,000. Which means that unless the competitors ’keep up with the Joneses’, they have a built in disadvantage in races.
The question is, are you competing at a level that would require you to spend that much? If not, the difference between a 15,000 bike and a 5,000 bike would be vanity? Nothing wrong with that, particularly, especially if you have that sort of money as disposable.