I always found it so fascinating how a new startup/unicorn that has 0 revenue can be valued at 10B when a company like Altium that has a good amount of footing in the PCB/EDA world is only valued at 3.9B
My guess is that Adobe didn't want to pay enough cash and was going to be using too much stock in the deal.
Altium would be a bunch of fools for not cashing out right now, though. KiCAD is right about at the level where it is going to start eating the bottom tier of customers. Even 1000 users lost would be a big hit to their revenue.
We'll probably buy one last set of Altium licenses to support current designs, but KiCAD 6 will probably become our default PCB software in the next year.