Actually Laura reaches top 8 pretty consistently, especially in Europe. The problem is she usually gets beaten savagely when she gets there unless it's Krone or Strider.
Plaid_Unicorn posted a tweet the other day where it was shown that she's one of the most recurrent characters in top 8, but also that she's the character that loses the most once she gets there.
edit: found the tweet
The numbers within brackets are wins and losses. Laura is the 4 most present character in top 8s but only has a 28% winrate.
That's because Laura carries bad players to top 8.