The projects that I work with are mostly graphical and electronic on Windows and Unix. Problems with graphics on Windows and Xojo have been poor and have decreased. I can create a graphical program on C++, C#, javascript, or another language that is unoptimized on Windows and the program will always be slower with Xojo. Usually Xojo is approximately 100 x slower.
Xojo does not have access to DirectX, and modern OpenGL, or Vulkan, although it used to have DirectX and has version 1.3 of OpenGL from August 2001 (19 years old). The Xojo language or compiler, or something is highly hampered for graphics.
Xojo does have the ability to work with Linux, and again the language is hampered. Programming with the Xojo IDE is unoptomized and unstable, as it requires a frequent reboot at a rate of a couple of times per hour with Ubuntu.
Raspberry Pi was largely using wiringPi for electronic work, and graphics for Xojo are poor, as the controls are missing, or drawn incorrectly.
Yes, every one of these issues can have a plugin written to increase performance. When this is standard with other languages, and performance is much higher for a greatly lower price (often free), then users often see that Xojo is not growing.
Changing the language from Xojo API1 to API2 has also caused angst among members, as working programs and code for the last 15 years or so has become somewhat obsolete. Yes, you can rewrite 15 years of everyones code to make it work, and without automatically making changes, now most modifications are manually completed.
I have only had one minor call for porting an existing application from Windows to Apple in 30 years, so I can’t comment on this platform.
There is much more that can be said, and this is a good start. This is not to be construed as a rant, its just an accumulation of frustration amongst people who have left the Xojo platform. I would like to see Xojo do better, and will continue to use other tools until Xojo can determine the direction the corporation and language want to go.
More can be said, and has been said in the past, and I am just summarizing some of the points from dedicated Xojo followers to have moved to other platforms.