What makes you think they're not readily accessible? They are. Part of the issue is time. If you're a surgeon, one individual surgery is but a small part of your day. There really isn't any spare time to "prep" for a surgery other than reading the specific of that individual case.
The submitted article also discusses how a limiting factor is time rather than availability of simulators.
The author wrote: "The paper I published in 2019 summarized my findings, which were dismaying. The small subset of trainees who succeeded in learning the skills of robotic surgery did so for one of three reasons: They specialized in robotics at the expense of everything else, they spent any spare minutes doing simulator programs and watching YouTube videos, or they ended up in situations where they performed surgeries with little supervision, struggling with procedures that were at the edge of their capabilities. I call all these practices “shadow learning,” as they all bucked the norms of medical education to some extent. I’ll explain each tactic in more detail.
"Residents who engaged in “premature specialization” would begin, often in medical school and sometimes earlier, to give short shrift to other subjects or their personal lives so they could get robotics experience. Often, they sought out research projects or found mentors who would give them access. Losing out on generalist education about medicine or surgery may have repercussions for trainees. Most obviously, there are situations where surgeons must turn off the robots and open up the patient for a hands-on approach. [...] My data strongly suggest that residents who prematurely specialize in robotics will not be adequately prepared to handle such situations."
The author also listed examples of accessible simulators, notably one that uses virtual reality: "In the past five years, there has been an explosion of apps and programs that enable digital rehearsal for surgical training (including both robotic techniques and others). Some, like Level EX and Orthobullets, offer quick games to learn anatomy or basic surgical moves. Others take an immersive approach, leveraging recent developments in virtual reality like the Oculus headset. One such VR system is Osso VR, which offers a curriculum of clinically accurate procedures that a trainee can practice in any location with a headset and Wi-Fi."