Complex sentence: By 1969, other movie studios had discontinued their animation departments, leaving Walter Lantz as one of the only two producers still making cartoons for theaters, the other studio was the upstart DePatie-Freleng Enterprises working for Lantz' former contractor, United Artists.
Split into simpler sentences: By 1969, other movie studios had discontinued their animation departments, leaving Walter Lantz as one of the only two producers still making cartoons for theaters. The other studio was the upstart DePatie-Freleng Enterprises working for Lantz' former contractor, United Artists.