Correct, you can do exactly that.
Or, in more words as Qt pusts it:
> Starting with Qt 5.15, long term support (LTS) will only be available to commercial customers. This means open-source users will receive patch-level releases of 5.15 until the next minor release will become available. This means that we will handle Qt 5.15 in the same way as e.g. 5.13 or 5.14 for open source users.
It has nothing to do whether mirrors do exist or not, when there will be nothing to mirror.
> Starting with Qt 5.15, long term support (LTS) will only be available to commercial customers. This means open-source users will receive patch-level releases of 5.15 until the next minor release will become available. This means that we will handle Qt 5.15 in the same way as e.g. 5.13 or 5.14 for open source users.
> But last week, the company suddenly informed both the KDE e.V. board and the KDE Free QT Foundation that the economic outlook caused by the Corona virus puts more pressure on them to increase short-term revenue. As a result, they are thinking about restricting ALL Qt releases to paid license holders for the first 12 months. They are aware that this would mean the end of contributions via Open Governance in practice.
[0] https://mail.kde.org/pipermail/kde-community/2020q2/006098.h...