I hate to defend Epic on this, but while indeed giving away games devalue them, and does make more people wait for a possible EGS freebie, the problem didn't start with Epic.
It's a mentality that has taken over most PC gamers. Almost no one buys indie games at launch. They wait for a bundle inclusion, or a heavy discount.
People have come to expect these games to be bundled, or discounted, and you have people waiting, in some cases, years and years until a title is bundled, in order to play them. They feel no "need" to pay, and value, the work of most indie developers.
But then, on the opposite side, people keep paying ridiculous prices for any Nintendo titles, even if it's the 10th re-release on an old game.
Why? Among other things, because they created an image that Nintendo titles aren't discounted, so people pay for them, and place more value on them, despite in some cases being old titles, or even re-releases or new ports.
So yeah, Epic may be doing wrong, and acerbating an existing problem, but they surely didn't start it.
Personally, I feel much more pleased about buying an indie title, than supporting a company like Nintendo, who is a multi-billion company, but that's just me.