Except it's simply not true. Instead candidates focus on a set of fairly high-population swing states, Michigan, Wisconsin, Florida, Virginia, North Carolina, Ohio, Pennsylvania.

That only makes sense if you believe that land area is the appropriate unit to attempt to equalize political influence over, rather than people. If you think the people are who should have political influence in a democracy, rather than units of land, then it should be desirable that politicians campaign to as many people as they reasonably can.

It's not equalizing political influence between states (that is, bringing them into equality), just bringing them somewhat away from inequality. (Also, states don't have equal land area, it's more like political districts.) The electoral college gives votes as a linear combination of "per political district" and "per people", with 435/538 = 80.8% being "per people".

Also, I guess it's the fact of "winner takes all within a state" that disincentivizes candidates from simply drumming up more support within states they've already won, more so than the distribution of votes per state.

Land area is not the appropriate unit. States are the appropriate unit.

Absent the electoral college there would not be a United States of America.

The parent comment referred to sparsely populated states. That is a function of population and land area.