I wonder if that hurt its adoption since a lot of graphic designers use Mac, so their first impression of Inkscape would've been very poor?

Unfortunately they have only a fraction of the resources of adobe and their development has slowed significantly over the years.

Their product is just too cheap. It might as well be free. They charged something like less than $50 for a one time purchase and only required a paid upgrade recently after like 7 or 8 years.