It would be tough today.
Both are worth about the same — $130b, plus or minus.
Mergers of equals sometimes work, but generally when it’s a huge bet that either 1+1=3, or more often, that for both, the world is changing so quickly, they need to bulk-up together.
If Adobe was worth 3x or more than Salesforce, it might make sense. Adobe’s Marketing Cloud is enterprise-enough and adjacent-enough, for a combo sort of kind of to make sense.
Still, the DNA is pretty different. With identical market caps, it’s pretty tough.