Only if you have decided that English PL players don't match up to their South American peers. Take Charlie Austin for example, he is far more than just a striker and yet even though having scored 17 goals and still in the race for PL Top Scorer, playing for a team struggling to stay in the division, which certainly doesn't help, he often fails to garner the plaudits in comparison to those around him, Kane for example (yes, I know he's English - but he's fashionable and has dropped like an A-bomb from nowhere).
I don't think anyone here underrates Benteke and Berahino has pace to burn and goals (though temperament/attitude could be dodgy).
I agree it's not easy, and overall there's a lack of depth of striking talent in the PL, but even if shopping in Spain it's still not easy to pick a free-scoring, reasonably priced, striker with PL potential. As I said above though, Lacazette & / or Firmino would be my preference.
If we were to take a current PL striker then Benteke would get my vote, he could be very helpful in assisting fellow Belgian, Origi, to settle into the PL. Austin wouldn't be far away though, for his all round game.
Actually talking of Benteke and Austin brings a major Liverpool weakness to mind. A lack of headed goals. I simply can't remember any this season, though maybe there are 2-3. However I saw a table last week showing those teams with the most headed goals this season in the PL, 14 I think was the leading figure, United were about 5th with 8-9, I can't remember the details. However that is a serious weakness in our team and we need a striker who can re-instil some form of aerial threat.