I think you are misunderstanding what I'm saying. Think of it this way -- people often say that Republicans automatically get 35% of the vote, and Democrats about 35% of the vote. In Texas, it is more like Republicans get 43% of the vote, and that Democrats are more like 25-30%. So, that means that Beto needs at least two thirds or so of the Independent vote.
What Beto did in Texas was very impressive. To give you an idea, a Democrat has not won a Senate seat in Texas in 30 years, and Beto's loss by 2.5% was the closest Senate race in Texas in that 30 years. The final margin was almost 5 times closer than any election for Senator in that time -- the next closest was an 11% loss (in 1996 -- over 20 years ago). Perhaps a better comparison, Sen. Cruz won the 2012 election by 16%. It wasn't an 8% deficit Beto was trying to make up.