This is a field guide, not a prediction. Every category here is one I have bought from, sold to, or built a competitor inside over the last fifteen years as a CPO. The pace of what is happening to software right now is faster than anything since the move to mobile, and most of the destruction is happening underneath teams that have not noticed they are exposed.
The three forces
Search is becoming answer. The user types a query, the answer engine reads ten sources, and the user gets a paragraph with citations, no click required. This kills any category whose distribution depended on SERP clicks, and it rewires how you write content: optimize for citation in the answer, not for the click on the link.
Tool is becoming agent. An agent can read messy data, take an instruction in plain English, do the work, and report what it did. The human moves from operator to reviewer. This kills the category of "tool that helps a human do task X" whenever an agent can do task X end to end.
Subscription is becoming outcome. Seat-based pricing breaks the moment one operator with agents can do the work of ten, because your revenue drops as your product gets better. A per-outcome competitor undercuts a per-seat vendor by pricing in the productivity gain.
Three buckets
Already gone or going fast: Q&A reference communities, tutoring and homework help, standalone grammar and spell-check, transcription and OCR as a service, generic translation, resume builders, standalone copywriting, ATS keyword tools, generic stock photography, standalone scheduling links, and rule-based chatbot platforms. Each sat on one thin layer an LLM now provides for near-free.
Reshaping at the core: search engines, BI dashboards, CRM, tier-one support, email marketing, SEO tools, project management, wikis, survey tools, coding bootcamps, and design tools. The product is not disappearing, but the shape changes so much the team is likely shipping a different product by end of next year.
With moats: regulated vertical SaaS, identity and security, hardware-attached software, marketplaces with network effects, data plumbing, payment rails, and industry systems of record with high switching costs.
What to do this quarter
Pick one workflow your users do inside your product today. Just one. Prototype it as an agent flow the user reviews, and ship it behind a flag to five customers. Add one outcome SKU next to your seat pricing and get one customer on it. Rewrite your top pages for citation, with a summary block, FAQ schema, and named entities. And write the one internal one-pager naming the most likely replacement product for your category in 18 months. Do that last one this quarter and do not let it slide.