For starters, actually trying to deliver what they promised? Get the actual hard, boring job done bigger clients wanted. The not-sexy work behind the scenes. Main problem is that it doesn't look good on paper, and Twilio hired an absolute insane amount of people.
My guess is they profited _a lot_ from the crypto hype. Exchanges sprung up right, left and centre and they all needed customer call centres etc. So Twilio grew through that. Saw super high growth and thought: All is well. All the while the "real" customers didn't get the features they needed, and quit Twilio after a 6 month trial period.
I had the "pleasure" working for Twilio for over 4 years. I cannot tell how much this showed me how you can fake it til you make it in SF.
Twilio tried to expand into Europe and failed miserably. Customers (especially German ones) wanted exact locations of data, exact routes of packet transportation, wanted features Twilio promised on Slides but never delivered.
I was part of at least 4 customer meetings (the biggest in Europe) where the clients just called Senior levels in and told them off.
Twilio was great when it just handled voice and text messaging. It never grew substantially, it never delivered features customers were asking for years. Messy code base, hired product owners with no clue what they should actually build.
Jeff was famous for over-promising and under-delivering. 1 year into my Twilio career, it was clear that the company would fail hard. Colleagues and I had bets on when Jeff will be fired or the company sold. Well, the last few months have been telling.
A sad story, since they had a great core product, really smart people, great people working there. But especially through the pandemic, they grew an insane amount without actually building anything of substance.