Investors have been increasingly skeptical about the future sales growth of Adobe’s products for design professionals, which increasingly have been seen as cumbersome, expensive and outdated. Upstarts like Figma, Lightricks Ltd. and Canva Inc., which offer more consumer-friendly services, have dented Adobe’s once-unquestioned dominance. The maker of Photoshop relied on acquisitions as it increased sales an average of about 20% a year since 2015 to an estimated $17 billion, but most of the purchases have been in adjacent business or new sectors such as marketing, e-commerce and analytics.