I will, as you say, carry on with business as usual. For the following reasons.
1. Like yourself I am older (65) and no longer a professional player. It is all for fun and self satisfaction.
2. Sonar should run for a long time without problems. Make sure you have all pertinent files downloaded and duplicated. If one source becomes unavailable for whatever reason you will have a duplicate copy.
3. I understand that professionals need another viable platform to continue their business. However for us non professionals their is no rush. Every year there will be Black Friday and Boxing Day sales and we can, when we want, buy an alternate DAW at a good price.
4. For me to search for, and buy a new DAW before there is certainty about Sonar's future seems premature. Who knows, some company may buy it and continue its development. I think the chances of this are slim, but it could happen.