[ For the record, not an invitation to a futile further debate, given your long-standing immutably-held views on DNSSEC. Since you'll probably say the same about my work to get DANE for SMTP up and running, we can stop here. All I can add is that those who say it can't be done should not get in the way of the people doing it... :-) ]

No, the major providers did not get together to do MTA-STS because DANE was bad. They did it because their existing DNS geo-balancing kit for e.g. google.com and yahoo.com does not offer an easy upgrade path to DNSSEC. Note that Microsoft has a dedicated domain (outlook.com) for email hosting, and can more easily do DNSSEC there without impacting their other "web properties". Note also that Google now MX-hosts many customer domains on "googlemail.com" rather than google.com.

So things are starting to change. Furthermore, there are now over 1 million DANE-enabled DNSSEC domains. MTA-STS is far behind, is not downgrade-resistant on first contact and uses weak CA-leap-of-faith DV authentication. It will probably be enabled at the biggest providers by the end of this year, but as you yourself said elsewhere, these providers are the threat, and if so, securing email delivery to the user surveillance empires is not necessarily that important. Mind you, they can play a useful role by enabling validation and helping to keep the TLSA records of receiving systems valid, and perhaps surveillance is not their business for paying customers...