Yea and no. The email “big tech club” happened under a pretense of spam blocking because back then spam and bots were a new concept. We now know a bit more about it and have anti-spam measures built into, e.g. even lemmy so I don’t think big tech will be able to use spam itself to piggy back on. At the same time Facebook has already announced Fediverse integration, and while there’s a petition to defederate from it as soon as they bring their servers up - what’s going to happen if Facebook+Twitter+Reddit decide to hop on the fediverse bandwagon? There’s just too much juicy content there right now. The FOSS Fediverse will have a tough time choosing between accessing all of that juicy content or keep the team values up. Now all of the mentioned sites are in decline, so as long as FOSS fediverse gains momentum faster than Big Tech unites I think we’re safe.