Because of the economics of software R&D. Professionals are not willing to stand around a tool that does not do what they need to make money themselves. They simply want to pay and use for a "finished" product, but never stop to consider that (a) software is never finished and (b) funding its development does not mean that you need to use it exclusively.
Companies/professionals would stand to benefit a lot if they funded FOSS alternatives, even if just as an hedge against their "main" tool. Imagine if every design agency got 5% of their "Adobe Tax" and donated to the devs of Penpot, Gimp and Inkscape. No strings attached, just with a "here, none of you need to worry about funding". In just a couple of years all these OSS tools would catch up, and the companies would be able to at the very least use the existence of FOSS alternative as a negotiation tactic when dealing with sales team from Adobe.
Because of the economics of software R&D. Professionals are not willing to stand around a tool that does not do what they need to make money themselves. They simply want to pay and use for a "finished" product, but never stop to consider that (a) software is never finished and (b) funding its development does not mean that you need to use it exclusively.
Companies/professionals would stand to benefit a lot if they funded FOSS alternatives, even if just as an hedge against their "main" tool. Imagine if every design agency got 5% of their "Adobe Tax" and donated to the devs of Penpot, Gimp and Inkscape. No strings attached, just with a "here, none of you need to worry about funding". In just a couple of years all these OSS tools would catch up, and the companies would be able to at the very least use the existence of FOSS alternative as a negotiation tactic when dealing with sales team from Adobe.