Anyone expecting the same level of service as Genelec, a brand that has been established for decades, employing hundreds of people directly and likely relying on a similarly sized dealer network is vastly over estimating the capabilities of a start up without VC backing.
And even with the efficiencies of scale and having amortised a lot of investment, Genelec remains very expensive. They provide a lot of ancilllaries around theirs speakers, software support, fast repairs, known reliability... But if you care about that, the Genelec 8040 is available at Thomann for 1900€ and at Sweetwater for 2500$, and I have no doubt that its measured performance at in the realm of the C6B and a decent class D amp.
If you wanted Genelec levels of service, it was already available at Genelec pricing. And to be fair, plenty of people and businesses have made that choice because they needed or wanted that level of service and polish. It is an excellent choice.
On the higher end of the price range, from everything I know, D&D offers outstanding service, and their 8C is directly comparable with the C8C with some added niceties, but it's also nearly three times more expensive. The same goes for Kii.
As for well measuring DIY speakers, they exist and are numerous, how many of them are available for purchase (even with a delay) at 1300€ (Audiophonics pricing for C6B)?