If that's what the article said, or if that's what the poll underlying the article said, then I agree with you at least to the extent that Hillary would be sitting in the catbird seat.
But neither the article nor the poll say anything of the sort.
Here's a link to the actual raw results of the poll mentioned in the article:
https://mediarelations.gwu.edu/sites/mediarelations.gwu.edu/files/GWBattlegroundPoll57-toplines.pdf
Scroll down to page 5.
You'll note that for Hillary Clinton 47% of likely voters polled would consider voting for her and and 51% would not consider voting for her.
Then look at Marco Rubio; 42% of likely voters polled would consider voting for him and and 50% would not consider voting for him.
If they were the two candidates it would be a pretty tight run race.
Clinton would get 47% of the voters right out the gate and Rubio would get 42%.
That's 89% of likely voters accounted for.
Let's next look at the voters who wouldn't consider voting for either candidate.
For Clinton, of those who wouldn't consider voting for her, only 7% would "somewhat" not consider her but 44% would "strongly" not consider her.
For Rubio, of those who wouldn't consider voting for him, 18% would "somewhat" not consider him but only 32% would "strongly" not consider him.
With Clinton, 80% of the people who don't like her
really don't like her.
For Rubio only 60% of the people who don't like him
really don't like him.
So let's assume for the sake of argument that, given only two candidates, each will pick up the votes of those who only somewhat dislike them.
Of the 11% of the vote that's still unaccounted for Rubio will get 40% of that (4.4%) and Clinton will pick up 20% (2.2%).
That puts Clinton at 49.2% and Rubio at 46.4% with 4.4% off voters still unaccounted for.
As you have to see by now, that does not, in any way, equate to a 48% Clinton lead over ALL likely Republican candidates.
And this is before things like actual campaigns, and investigations, and PACs, and debates, and GOTV drives, and the dispersion of the vote, and the electoral college come in to play.
Before any of those considerations, based solely on the raw numbers in this poll, and assuming all likely voters actually vote and the two candidates evenly split the 4.4% of voters we haven't yet accounts for, yes, Hillary wins.
But there's a big difference between being the frontrunner by 2.8% of the vote in a poll taken a year and a half before the election and being the shoe in you are assuming Clinton to be.
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