My last word on this topic, as you say Biggles, it has rather strayed from the original thread.
There is very little (Windows)software that can't be made to run on current computers, some with the right version of Windows, e.g. Pro. You can run programs in compatibility mode (right click on the executable, go to Properties/Compatibility) etc., you can, as I do, run programs in virtual machines hosting different operating systems. There are emulators available, etc.
My PC is the equivalent of Triggers broom. I have not bought a new PC since the early 1990s, when I replace my Amiga with a Windows PC. Periodically, it has received upgrades to its motherboard, RAM, processor, discs, case, keyboard and mouse, monitor, and it is now effectively no longer the same computer at all, but I have installed new components in stages rather than junking it and buying a brand new machine. It currently runs Win 10 on the primary partition, and Win 8.1 on a second partition. I have no wish to "upgrade" (which is not neccessarily an upgrade in the true sense of the word, at least at present) to Windows 11, but should I wish to do so in the future, I only need to add a TPM module to my existing motherboard to meet the installation requirements. It is also possible to install it on machines that don't meet the full requirements, as long as you are happy to support it yourself.
My intention, as set out in my Will, is for my research to be donated to the Society of Genealogists.
See
https://www.sog.org.uk/support-usSeveral family members already have printed and digital copies of my research. It is possible to produce books and complete websites from the genealogy software I use with relative ease. I have already produce booklets on a few of my lines, with copies in the hands of a few interested relatives. I intend to do so for others when my research reaches a point that I consider it sufficiently worthwhile.
But that aside, whilst I do have "recent" copies of my tree on various genealogical websites, by placing all your data on a single website, you are assuming that also will never be lost, damaged, corrupted etc. It may seem unlikely now, but Ancestry in its current form for example, didn't exist 30 years ago. Can you be sure it will still be around in 30, 50, 100 years?
But I find online trees impossibly clunky to navigate and use effectively. When a name crops up in your research, how easy is it for you to search your entire tree to see if it has cropped up in connection with any other family members or events; as a witness at a wedding, neighbour in a census, mentioned in a newspaper report alongside a relative, etc? It may be possible, I don't know as I don't wish to use an online tree to conduct my research, but such a query takes a matter of seconds using my software.
How do you record your DNA matches in an online tree? Yes, I know they are shown with an icon within the tree itself, but how do you easily compare match lengths, MRCAs, the companies they have tested with, their relationships to you etc, all in a list that can be manipulated for searching or retrieving information, or exporting to a spreadsheet for analysis? My guess is that you would have to do it outside of the tree. I can run another set of queries in seconds and find any of that information that I need.
If I want to know who might be missing from a particular census, you guessed it, I run a query.
If I want to see where all my relatives lived, or a timeline of where a single relative lived, or a family group, I can show that on a world map.
If I want to find out which relatives had a particular occupation, it takes seconds, etc. etc.
So I'm sorry, but an online tree is not for me ever going to be a suitable primary repository of my ongoing research. If it suits you, that is fine. It's not my intention to criticise, just to explain my position.
With my tree constantly updated onto several different media and offsite backups, I think I am at least as well and possibly better covered against disaster that a single on;line tree. Again, you might disagree. That's fine, and if you are happy with your arrangement, who am I to criticise. I am just explaining my methods, and my reasoning.