That is not exactly a career then. You will only be an expert in a trendy technology. I expect a real senior software engineer to be above the newest trend. I do not want him to understand react. I want him to understand the reactive UI concept (which is applied in React, Angular and maybe a 30 year old tech). I expect him to be capable of learning the newest trend within days and also expect him to understand the 40 year old language and the code style written then. All of that, I do not find in someone who burns himself to become an expert in a trendy tech every 3 months.