What mainstream software product do I use on a day to day basis besides Claude?

The ones that continue to survive all build around a platform of services, MSO, Adobe, etc.

Most enterprise product offerings, platform solutions, proprietary data access, proprietary / well accepted implementation. But lets not confuse it with the ability to clone it, it doesnt seem far fetched to get 10 people together and vibe out a full slack replacement in a few weeks.