Problem with coupe versions of existing products such as RX and NX is that they do not want to do it. Maybe they dont see the demand in markets Lexus sells well?If I was at Lexus, I would have to figure out a way to get these products faster to market without sacrificing quality. The fact is this vehicle is so late its not funny. The BMW X6 is in its THIRD generation. Look I am not at all a fan of coupe SUV's but from a business standpoint this is where the market has gone. Lexus should have a NX/RX coupe and a LF-1 by now. Again what perplexes me is these vehicles are not all new from the ground up. They are mix matches of existing parts. The Q8 is a Cayenne/Urus blend for example.
As to the Q8 and Cayenne, that is probably more similar to Rav4 and NX, as supposed to LF-1 and LS for instance.
What would be simpler is something like RX and RX-C where they would be developed together and that would make it much cheaper, but again, they do not want to do that.