Big data is dead?

Depends on company to company. For tiktok and social media companies - it is must. For something like. Zerodha I don't see any need because that's what their philosophy has been. I work in a company with quite a bit of use less (literally) data scientists. But that's true for all jobs / domains.

Big data was never alive for most companies. And most DA/DS work can be done by regular SWEs unless it's research or model validation.

Data engineering is definitely not dead. I work for a large retail chain in Australia and this is like bread and butter for retail industry. Everyday TBs for data gets processed for variety of usecases. And obviously, this infra can only be developed after having your backend infra. So not a primary function but secondary for some industries, totally!