Nah. The main impetus to achieve FTL communication will be because it'll be easier than shifting people off of TCP.

It’s all fun and games until you get an ACK before you sent the SYN.

That's a solved problem, just ask the thiotimoline research group.

https://en.wikipedia.org/wiki/Thiotimoline

Tardis Control Protocol.

I don't think volume of data average user will want to send to Mars over next 100 years will be a important factor enough. I envision Mars comms using some kind of relay service, to which you'd communicate using TCP

Earth-Mars will be a store and forward network not unlike the old UUCP or BBS networks like FidoNet. You will send blobs of data via something that probably looks like a replicated S3 bucket and get notified when replication of an object has occurred.

IP is usable to the Moon but a lot of protocols would need latency constants adjusted and very large packets would be desirable. Store and forward with custom replication protocols might still be more efficient for large volumes of data.

i'm not sure about that statement. See https://en.wikipedia.org/wiki/IP_over_Avian_Carriers

That's IP (and ICMP for ping), not TCP.

Yep yep yep, Long Fat Pipe problems, right.

More likely, we will end up with 15 competing standard.

https://xkcd.com/927/

That assumes that the speed of light is an insurmountable speed limit. We can't be 100% sure of that.

But even if it is, TCP can be used with any latency if you configure the timeouts accordingly and maintain a large enough send buffer to allow retransmissions.