Will Core ever adopt Segwit by default? There is no excuse for current companies that do not adopt Segwit. It looks very scammy. 

However, does Core plan to adopt Segwit by default at some point? Is it a matter of money or anything else?

Just being curious. Thanks.
Full SegWit support in the Bitcoin Core wallet is planned for the next release.

It is a matter of testing and review: https://github.com/bitcoin/bitcoin/pull/11403