Texas is a big state, as any Texan will tell you. Like most Americans, my experience with Texas is more with the myth than with the fact. My entire experience in Texas amounted to four days in Dallas and Denton, which gives me a very narrow window to understand Texas.
Texas has been, since 2008, the great white hope of the Democratic Primary. As the second most populous state, Texas' electoral votes are pretty much required for the Republicans to win. And as a populous state with a large number of minority voters and several large urban areas, Texas would naturally be a competitive state. And indeed, Texas is a bit more competitive than its image might portend. In the 2016, the Republican candidate won 52% of the vote, meaning it is getting close to being a swing state. But, if you were to ask the average Democrat, even a relatively knowledgeable one, about what Texas democrats might be like, they might reply "Latinos" or "suburban, college educated voters around Austin". And then the next question is, what do those voters want? Are they legacy Democratic voters who want a moderate candidate, or are they young, diverse, urban voters who want something more? Luckily, this debate in vague terms is cut short by the actual results of the election. Except where it isn't.
Several days after Super Tuesday, the results from Texas are more or less complete. Joe Biden won 34% of the vote, while Bernie Sanders won 30% of the vote. Michael Bloomberg and Elizabeth Warren both won in the low teens, and because of the way the delegates are apportioned, got only marginal numbers of delegates. In general, Joe Biden had a good night, winning most of the night's contests. Because of that, the narrative can exaggerate other victories. With 34% of the vote in Texas, and a 4% margin over the second place finisher, it is barely a sign of consensus. But once the map gets colored, Texas gets colored for Biden, and he wins.
Despite the weak percentage numbers the two leading candidates got, they were still a lot of votes in the raw sense. Despite primaries having generally low turnout, and despite the vote getting split three ways, both of the leading candidates got more votes (over 600,000) than the population of several US states. In fact, Bernie Sanders 622,000 votes in the Texas primary are just a shade under the current population of his home state of Vermont. The votes are out there, for the candidate who can get them.