Let me clarify that by no means am I a fan of the Lexus RC F. Its platform has barely changed since its introduction in 2005 with the IS and GS sedans. It's weak compared to the rest of the D-segment especially with its porky curb weight figures. HOWEVER, I would like to point out that contrary to the majority's belief about the Lexus RC F, the car was not ever designed to tackle the BMW M4 or Mercedes-AMG C63. The RC F was supposed to be a comfortable cruiser with extra performance and purity for the modern driver.
The RC F is not an M4 or C63 competitor at all, but it's also not a 440i or C450 competitor (the M440i and C43 weren't even out yet). It's not highly expensive either, all Lexus F Performance models start at near fully-loaded prices, as opposed to Audi S and RS, BMW M, Mercedes-AMG, and Porsche cars.
The Lexus RC comes with much higher tech, more front legroom, and a much longer and more radical-looking front clip than the IS. It's more like the BMW 6 Series and Mercedes-Benz E-Class (2-door variants). The RC was not designed with sportiness in mind.
The M4 and C63 might have started at $5k more in MSRP, but loaded up with a maximum number of options their prices climbed up to $100k+. The RC F, only around $70-75k (unless you opt for the Carbon or Track Edition models).
Lexus is not a high-tier luxury brand. Instead, it's more like Cadillac, Lincoln or Genesis. It's certainly higher than Acura and Infiniti, that's for sure.
The RC F's main competitors were the RS5, 650i, and E550 coupes (in terms of both overall size and performance), but it started at the same price as a mid-loaded RS3, a mid-loaded M2 (but not Competition or CS), and a mid-loaded CLA45 AMG.
Lexus is pretty much a mix of Cadillac and Dodge, but headquarted in Japan right next to Toyota. A big car with high performance priced at the same level as a sport compact = a muscle car or pony car.
TL;DR: The RC originally creeped into E-segment, but given the outdated tech it barely rivals the newer D-segment coupes. The high-performance C-segment premium cars are more expensive than the RC F and its IS500 F Sport Performance sedan sibling, fully loaded versus fully loaded.
