The Litvishe gedolim only recognize the “need” for the secular studies as a b’dieved because the government requires it and if they didn’t offer it many parents would not send their children to a good yeshiva
That may have been true initially, but after seeing the products of both types of mesivtas, they would have a secular program even if there were no government regulations or parental influence. Nowadays, kids that age can’t handle a full day of learning, and a secular education, aside from having its own value, is far better than the other ways the boys would otherwisw spend their time.
Sure, it would be great if kids could keep an intensive, 12 hour a day learning schedule. But they can’t.
There is also no valid defense for having a shoddy secular studies department. Once there is a secular studies program, whether you think there should be one or not, it should be well run and taken seriously. A shoddy secular studies program is horrible chinuch because it encourages poor work habits, and poor middos (because unless the secular studies are taken seriously, inevitably the students act disrespectfully towards the teachers. It’s also a chillul Hashem.