Digital might be just bits but it is always to be considered transitory
Just as you would expect a hard drive to perhaps die after 3 to 5 years, just as you would expect formats to become invalid, you should not use any online service as your only place to have your data. Similarly you should not invest too much into tagging, promoting, organising things online unless this has short term value or can be added back into your local data.
The main problem here of course is that it is not about the files, it is about the professional business presence for photographers - their storefront. Probably this sold copies, had modes for private wedding galleries etc. which are all gone and will mean a short term loss of business.
In that case the cloud convenience of a SaaS solution means one is at risk of one creditor pulling the plug. Backup, exports and static archives are all useful ways to get some prevention. I would also say that a SaaS solution based on an open source product has an advantage here, because you could have backups and exports running on a copy fast.
But all the prevention in the world - contracts that specify source code release on bankrupcy, data and template copies etc. - cant help if the company doesnt do the right thing, if they just pack up and vanish.. but that is NOT just a cloud problem, it can happen with a normal hosting company