You know this is a risk. If you went deep on something like Silverlight, you'd have just thrown away all that time. And then people will casually dismiss your 10 years away as not being relevant. And now you get to pick a new technology to maybe invest the next 10 years on, risking the same thing happening again. If a product dies, you go back to square one as a junior again on some new technology.
Picking a long-lasting technology is hard. You're predicting the future.
I'm really tired of people who think they have this industry figured out like it's easy to predict what will be around in 10 years so you can make safe choices about what to invest time into.