Avoid starting a new business under an older version of a platform because they are often out of date, with no guarantees and support. There will also be a relatively large cost of time and money with upgrades, not to mention bugfixes that are usually fixed in newer versions.
Note that this is not just for Magento. This is true for any platform.
There may be exceptions where you will be forced to use an older version, but this is very rare and can be solved in smarter ways to avoid the use of something out of the way.
Additionally, you should also avoid "abandoning" the platform. Whenever an upgrade occurs, do so in a test environment and then upgrade to the production environment.
Therefore, once installed, it needs constant maintenance.
These popular platforms are always launching new updates on an average of 1 every 2 months. Each of these updates brings various changes and usually bug fixes and may also cause new bugs that need to be fixed as quickly as possible.
Do not let yourself upgrade after 1, 2, 3 years, for example, because it usually becomes a nightmare due to unexpected bugs.