I think its more of down to how good/shrewd Klopp is and their scouting/youth system.
Their replacements and signings are almost all nobodies at first too, but they manage to integrate it perfectly into their system. Lewandowski, Gundogan, Piszczcek are nobodies at first too. Perisic and Leitner too to a lesser extent. Only Reus was a big spend.
Meanwhile we lose players every year and sign underwhelming players. Sometimes we don't even sign anybody and promote youths who are clearly not ready. We does do well to strengthen areas we are weak at, but yet at the same time lose players from positions we are strong at. That happens every year. Wenger's coaching has stagnated imo as well.
