You have mother plants done there fruiting in year in pass.

Mother plant fruit in summer then sin out runner that root and make fruit next year and after fruiting sin out more runners called baby plants that fruit the net year.
This cycle means remove old mother plant in winter after babies well rooted. The plants have to renew every year.

The plants do not have to renew every year, they should produce fruit for a few years t the least. Has it been extremely hot in your area lately? Blossom drop is usually due to high temps.

Eventually they will stop producing, and you will need to replace them with new plants or allow some runners to root as long as the mothers are still healthy plants. If they are blooming, they will still produce berries, so it is probably something environmental, most likely high temps...