Hmmmm,
The online retail price variance of most bike parts isn’t really that much typically…
Ultimately the price you find via the standard searches on say google, eBay or Amazon are probably going to yield up the cheapest (delivered) price.
Your proposed part finder service would have to bypass the various retailers and go direct to manufacturers or regional distributors to score any meaningful cost saving to you, all of which isn’t really in manufacturers or distributors interests. The industry has a tiered distribution model that mostly works (for those on the selling side) and is happy to let retailers fight over a couple of quid here and there in the name of competition.
The few companies that do direct distribution seem to hit a bit of a glass ceiling where their brand becomes less desirable as their prices become more competitive, again it’s not in their interests to opt into a price finder service, they’ve already dodged some tiers of the traditional distribution/retail pyramid and control 100% of their distribution and pricing, Why would they add an extra layer of cost that won’t yield a vast leap in sales?
Ultimately there is a reason you’re after a ~£70 pair of bars rather than the ~£30 pair with similar width/rise/sweep/weight you could score from some other brand. Deity know this and set their RRP accordingly.
Hence the best price Google provides is about what you’ll manage, it’s hardly “trawling” a five minute search, bang in your card details and wait a few days for arrival (or a call from your bank’s fraud detection team).
Hooray for the internetz!