Yes to the reasons mentioned above, i'd like to take it a step further and say that one should only keep plant varieties going that will produce
enough viable seed, otherwise try a new one from another producer. Best would be a seed exchange or get it from neighbors. Getting seed that work to a seed exchange means that others can mix all varieties and
landrace themselves. Sorry if i'm too optimistic.
You can try to start earlier and have all your seedlings killed and try again. You can give some to other people who'd like to start, or exchange or
sell. It's very valuable that if you have a collection of varieties that work in your area that people that want to start can start with something that works.
It's very discouraging that seed companies sell from the best soils possible, weak varieties that need a lot of tending to and chemicals instead of selling seeds that will work on the most terrible grounds without chemical molly coddling.
This man shows what one can do in a small garden.