Huh?
Honestly, I'm having a hard time following exactly what you're responding to here… "not really" what? You're "not really" assuming your methods are better, despite not actually having any? You "don't really" think that such training isn't possible? Or "not really", it's not such a stretch to think that, as you seem completely unfamiliar with the idea of mental state training (as seen in traditional systems), that you don't actually have any such methods?
I mean… here's the build up to your post…
So… which is it? "Not really in regards to basic mental discipline"… without context, I don't quite get what you're saying here…
But, to address the second part ("… mental discipline. Which i think is achieved through doing hard tasks diligently. And not through some sort of specific mental discipline/clarity exercise.")… frankly, all that tells me is that you really don't have the first idea what we're talking about. Yes, there are specific training exercises and methods for addressing mind-set. No, mental discipline isn't really what we're talking about (it's part of it, but really quite a fair bit below the level we're discussing)… that's, as you say, just part and parcel of doing anything with dedication. What we're talking about is developing specific mind-sets… not just "being disciplined". Each art has it's own specific mindset, for example… this is far more prominent in the classical systems, when you really look at them for the record. The "mind-set" of Tenshinsho Den Katori Shinto Ryu is different to the mindset of Hyoho Niten Ichi Ryu, which is different to the mindset of Hontai Yoshin Ryu, which is different to the mindset of Muso Shinden Ryu, and so on and so forth. Is there cross-over? Absolutely. But they are all different, in their own way, with differing emphasis' in different arts.
This is what we've been saying… the base level approach to mental training you're talking about isn't really anything like actual mental training as addressed in classical systems.