I have purchased quality interactive fiction before and not only in the 1980’s with Infocom, Scott Adams, Rainbird, etc. One reason I did it was for a very long form IF involving a period piece set in the 1930’s that came in a beautiful box with feelies like the ones Infocom used to do.
But this is a seriously niche market now and that was 1999 or so; the amount of super high quality free IF is through the roof now compared to then. An established author could probably get me to splash out, but newer authors would definitely have to put substantial demos out to attract me or other long term fans of IF.
Having said that, I have seen and purchased a few quality IF games through itch.io and through Steam. Most of them if not all of them do have illustrations (static, pencil black and white sketches or sometimes other things but usually the graphic is static or maybe a short repeated animation). Maybe a pure text adventure would be harder to sell.