Did anyone suggest otherwise?
With regards to total light, photons, or, equivalently, lumen seconds (luminous energy). With regards to exposure, photons/area, or, equivalently, lux seconds (luminous energy / area).
So, now it all makes sense to you, right? 😂😂😂
Let's take it down a notch -- more light, less noisy photos. But also, more light, greater amount/risk of blown highlights. Also, to get more light, we have to either use a wider aperture, resulting in a more shallow DOF, a longer exposure time, which increases the risk/amount of motion blur, and/or add in artificial light, which changes the lighting of the scene.
Can't technology and/or software make up for less light? To an extent, yes. I mean, if you're well within the "operating envelope" of a system, then if you're off a stop from the "ideal exposure", it's not going to make that much of a difference. But when you're near the edges of the "operating envelope", being off a stop can be a big deal. So, the more you're near the extremes, the more important this stuff is.