Dragging this post back up because I was thinking about something similar to this myself earlier today.
I think XSTP's are very capable of making art however I think how 'good' they are depends on the environment, circumstances and what you class as 'good' art.
I was thinking about my art class at school and there are five of us and we are all as different as you can get (in terms of mbti types we have an ISTP, ISFJ, ISFP, ESFP and ENFJ).
In terms of who does best in school, the ENFJ and the ISFJ. The ENFJ has the creative ideas, she's experimental and abstract however her drawing skills aren't as strong. The ISFJ is good because she is both expressive and personal in her art (being a sensor means she's also good with details though) and very organised and always on time). So if you looked at art in that way (who's most likely to succeed in an art degree or qualification) I'd say the ENFJ who is the epitome of your quirky 'modern' artist. She gets enjoyment from the ideas process and expressing herself. She's creative.
At the opposite end of the spectrum there's me. The ISTP. Now I'm not bragging here, I just know the strengths and weaknesses of my group, but I have the best technical ability in terms of observation, attention to detail and using my tools and materials. However I really really struggle with the creative aspect of the subject in that my work is not 'deep' or 'meaningful', and when it comes to project I'm really terrible at developing ideas. I get enjoyment out of showing my skill and making things look great, I have a good eye for colour and perspective and more sensory things. I don't draw to express deeper feelings, I draw because I like pretty things. Rather than projects, I'm better at creating one off pieces (especially because I get bored and have terrible time management on top of a not very 'artsy' thought process)
The remaining two, the ISFP and the ESFP, are in the middle. The ESFP is your quintessential ESFP. She's dramatic, emotional, materialistic and has a flair for fashion and textiles (so good in her own way but not as strong in what you might consider art as in paintings). The ISFP has a similar attention to detail as me, however lacks the confidence in her skills I have (but like me isn't great at being on time and developing her ideas and tends to do things just because it looks good but struggles following a project).
So to answer your question: XSTP's CAN create art, however each type has their own view on what constitutes as art. As an XSTP (actually I'm more of an ISXP but I fit your point), I know I view art as a demonstration of skill and the enjoyment comes from the actual composition as in it's colours, realism etc rather than it's message however others might view art more for it's expressional purposes which is why other types might be considered more artistic.
