No, its ubiquity does not belie its power. If you are arguing that earthquake is both ubiquitous and overpowered, then its ubiquity would be demonstrating its power. This is not necessarily true, incidentally; in any competitive metagame it frequently happens that players get swept up in a wave of popularity for a given strategy even if it's not actually particularly overpowered. Oftentimes this is a cyclical effect; one strategy gets really popular, so people start switching to a counter-strategy until it becomes really popular, then people move on to a strategy that counters that one, and so on.

In this case, I would note that mono-aether and mono-fire have both enjoyed quite a bit of popularity recently, although they seem to be on the ebb--probably due to the increase in earthquake denial decks. The addition of upgrades a week ago is also probably contributing to earthquake's popularity; while many strategies only saw modest benefits from upgrades to their core cards, upgraded earthquake decks are really brutal against non-upgraded decks (tower upgrades make it much easier to cope with earthquake, though). The popularity and demonstrable effectiveness of these upgraded decks is probably fueling a lot of copycat decks even among players who don't have the money to upgrade their earthquake deck.

So no, the ubiquity of earthquake neither belies nor demonstrates its power. While I can't argue that its prevalence in the metagame is heavily discouraging to mono-color decks... if you're at a rock-paper-scissors tournament and half the players are throwing rock all the time, your best bet is to not use scissors instead of expecting the tournament organizers to somehow nerf rock.