Is it true Romantic concertos were never written with specific performers in mind?

False. While some Romantic concertos were written without specific performers in mind, there are many examples where composers tailored their concertos to showcase the strengths and abilities of particular soloists. For instance, Tchaikovsky's Piano Concerto No. 1 was originally conceived for pianist Nikolai Rubinstein, and Brahms' Violin Concerto was dedicated to and influenced by the violinist Joseph Joachim.