Notes and Domino are still sold by HCL, but the market for people who can write LotusScript or understand a Notes data model has gone. Firms with decades of records in Notes databases find that every modernisation vendor wants to start from a blank database.
I spent thirteen years inside one firm's Lotus Notes estate, first building inside it so their investment was not thrown away, then lifting the records into SQL Server when the time came to put a client portal on top. Both are options: build inside the estate, or migrate the records to a relational store. Which one is right depends on what the records are worth and how the firm actually uses them.
Silverlight has no runtime left. The exit is screen by screen, not a rewrite.
LightSwitch generated your app. The tooling to regenerate it is gone.