A、Because the Parliament only supported Oxford and Cambridge. B、Because only Oxford and Cambridge were supported by royal patron

Right up to the 19th Century, Oxford and Cambridge were the only two universities in England. Royal patronage and aristocratic money confirmed them in their position, and attempts to found new universities elsewhere all met with failure. In the 19th century, however, other universities were at last established, though by private efforts and not through government policy. The first was in London, then in Durham and Manchester.
    The new universities deliberately challenged Oxford and Cambridge by choosing to study subjects like modem languages and English literature, which were not taught in the old universities. They got less influence from the established church and welcomed Catholics and even non Christians such as Jews as students. A larger number of provincial universities were established following their lead; these are the so-called "Redbrick" universities. Many of them were dependent on older universities at first, especially the University of London, but soon they became independent and began giving their own degrees. Many also became well known for their excellence in a particular subject and could offer a better course to students taking that subject than was available anywhere else in the country. After this first rapid increase in numbers and distribution, the number of English universities remained the same for nearly 40 years.
    But by the 1960s a new post-war generation had grown up. Due to an increase in the birthrate following the Second World War, the school-going population was bigger than ever before. Secondary education was better and the school leaving age became higher. Naturally the demand for university places became greater, and the government responded with an ambitious university building plan. Seven new universities were planned and built, and opened their doors to the new generation of students between 1961 and 1965. It was the greatest single expansion of higher education that England has ever known.