I have a somewhat unusual opinion. But for me, this is the only way everything fits together:
Not only was Simon announced so low-key, more importantly, nothing has changed to this day - he is still not included in interviews, not even occasionally, there has never been a profile of him, for example, in the fan magazine or anything like that.
I think he was meant to be an interim drummer while Steve decides what the future holds. Whether they willl continue touring or make an album...
For that period, he wanted someone who could play the songs reasonably well and with whom he definitely gets along.
Now that decisions about the future have been made, the real selection process will take place - who knows, maybe even right now, during the break in the tour.
Depending on the outcome, maybe an announcement will then be made that their touring drummer, Simon, is unfortunately no longer available for personal reasons.
While this would be disappointing for Simon, he will still be extremely grateful for the experience and there won't be any bad blood.