The reason the Federal Vision has been resurrected by people is that a) Moscow’s impact in the evangelical landscape is monumental touching members in PCA, SBC, and other variations; b) they also have invested much time in fighting the right culture wars, especially during COVID.
c) Peter Leithart’s @_Theopolis is gaining much ground in the intellectual arena with essays and discussions that stimulate greater theological and biblical insights than many other institutions.
d) Many find the need to narrow their Reformed focus as much as possible to keep as many people out as possible. The Federal Vision is a threat to this un-catholic vision.
e) Many have sacramental allergies and the FV brought issues of weekly communion and paedocommunion to the forefront of all these discussions stressing the objective nature of these rites and rituals.
f) Further, much of the FV revival is a sign that it has been absorbed into the Reformed mainstream, which means that those of us who indwell this world have won the bigger battle.
An example of this is how many PCA pastors find paedocommunion in its hard or soft variation completely acceptable. This was not the case when I began investing myself theologically before 2002.
Finally, the interest in FV stems from the sociological elements of the status of children in God’s redemptive history. How should they be viewed? If they are baptized, how does the covenant speak to such children, and what are the promises made to them?
Hurray! Also it takes a lot of shock troops in the pews to keep pushing back discreetly against unbiblical boundary excesses by pastors in the pulpit. I had to go head to head at that time with my own church’s session (part of the OPC denomination) when my young adult moved to another State and become a member of a CREC church. They basically wanted to excommunicate him (an eighteen year old with a stellar Christian reputation) for joining what they considered a heretical church. In the end they backed down. It was not fun, but God was at work.