I'm not sure. When I've travelled out and back on the train (using the RST concession is only for rail, obviously) I've noticed that everyone else leaves the station at Kingswear and continues on what is called the 'Round Robin' - open top bus and ferry.
It's a very commercial operation (that's not a criticism!) with very tight barrier control and 100% on train ticket inspection. Ticket sales at the station are only for the next train, and when it's full (seated) the booking office closes until the next train. Their loco utilisation must be the best in the whole railway industry - seems to be two locos working two diagrams day in day out.
You've hit the nail on the head- "it's a very commercial operation."
Whether running trains or doing engineering, effective commercial operations require a certain level of coherent management control and compliance systems.
From what I have seen in railway engineering across Heritage and different levels of mainline, tooo many Heritage organisations who do engineering are (at best) stuck somewhere around the 1980's in quality/process management. Even where there's a really good paid staff engineering core, they can be undermined when the engineering sheds become dumping grounds; when influential persons or those who hold a Board role own a loco, it's not unusual for the railway to become their free storage/workshop facilities, and volunteers are allowed to make the place untidy and have stuff everywhere. I doubt many Heritage people realise the value/cost of railway shed and pit/workshop space (or even siding space) on the open market!.
Similarly, when you have a management board and "Heads of" who are amateurs or retired senior fitters/Drivers/Guards who know the front-end stuff but never managed at that level, it's not always going to end well. Even where someone did a job like "Driver Training" in a mainline company, there they had the whole system behind them- someone else (usually several someone elses in fact) wrote the training packs and build the CMS that they used. There's quite a few in Heritage think they can build SMS's, CMS's and accompanying architecture but not many actually can produce something that is ailored for th eoperaiton in question, and would stand up to proper scrutiny in the event of an accident and full-on investigation; their competences/qualifications may similarly not stand up either. A lot of "old boy" connections and backy-scratchy in Heritage, and not a great lot of checking of professional indemnity insurance and qualifications (e.g. chartered in suitable professional body) methinks.
The "trust" type structure or PLC may not help as it too often decouples decisions from responsibility. It also makes it more difficult to make necessary-but-unpopular decisions and easier for a control-freak-on-an-ego-trip type character to dominate a railway and run it into the ground without any consequences. In a nutshell, the governance is not always good.
No doubt the pressure of COVID will have been the final load which broke a few crumbling structures, we'll find out in as the season unfolds. Llangollen may be the first to come to public notice but (unfortunately) I strongly suspect it won't be the last.
TPO