• Threads has begun testing integration with ActivityPub
• Tumblr, despite scaling down many operations for financial reasons, still has ActivityPub integration on the mind

The question is: how much money can they spare for integration? 

Decentralization apparently costs money if your site is built around centralized interaction. But, IMO:

• Smaller sites benefit in the long run because they can focus on taking care of those users who care to use their instance.
• Larger sites benefit by better moderation of content without as many users complaining about censorship. 

Better to shoot that shot now rather than wait and wither on the vine.