Both statements are suspect. Depends what you mean by Many. If by Many you mean a insignificant number when compared to the MCU fan base, then sure
And people under a certain age who arent movie buffs dont give two shits what Coppola or Martin think about these films or even know anything about them. Then theres a bunch of people who respect them as directors but just think they are old dudes yelling to get off they're porch.
None of this gonna have any impact except maybe open a dialogue about Block Busters squeezing Smaller movies out. Which is what Martin is talking about he said he hasnt even seen most the Marvel movies. Hes just talking about big budget Block busters in general. Marvel just happens to be the biggest franchise out right now.