This instrument was minimally adjusted at the beginning of the XXth cemtury, by John Phillip Sousa for his american military band. This instrument is called „Sousaphone”.
This examples already proves, that the size of the intrument was very soon limited its using possibilities and makers had to find a solution already for outdoor use, 15 years after the tuba was patent.
After the middle of the 20th century, Hindemith, R.V. Williams, and Penderecki wrote the backbone of the instrument’s solo repertoire. From the birth of the tuba it didn’t even arise for the instrument to be given a solo role.
Before the turn of the millennium, another major (film) composer, John Williams, composed a concerto for tuba, thus increasingly paving the way for a wider audience and to be a solo instruments.
Nowadays, more and more players, both technically and musically, are well prepared to stand up as a soloist with an orchestra or symphonic band, or play a complete solo recital.
During its evolution, tuba evolved in such a way that, due to its weight and holding position, it can only be played while sitting with it.
This is not a big problem yet, as they play both cello and piano by sitting, but in contrast, the tuba covers the player’s half face, the bell is not projecting to the audience and it is difficult to move the body while playing the instrument.