All other shimotsuki are fodders
Shimotsuki Tashigi will be the nail in the coffin for these copers and haters
Big mom has almost 100 children but they're not all Katakuri strong.
Even if your forefathers are strong and talented in something doesn't mean you just be it, you have to work hard and aspire to be that for the talent to manifest.
It just means after Ryuma, none of his descendants cared/were interested about being the strongest. They just became a simple Samurai who lived a simple life.
We saw how fast in strength progress the ones that cared about being the strongest was getting. (Kuina & Zoro)
Just because my family is known for being very talented in sprinting does not mean I will be the best sprinter if I never cared about being the best.
Your talent blooms only when said talent is your goal and mission.