Let me explain PvP in a very simple way

[Absimiliard]

Ya'll are forgetting the most frequent variant (as pertains to Frontlines specifically):

Team A plays well (or more likely gets lucky) and takes an early lead.
Team B and C then spend the entire rest of the game tunneling Team A, both disregarding the map's objectives and failing to notice at any point both of them have long since overtaken Team A's score.
Team B and C continue doing this until the end of the match, thereby needlessly dragging it out through their own lack of situational awareness.
Team A meanwhile has been locked in a cycle of gaining and losing people since the moment B and C put them on the back foot.

[ZephyrMenodora]

Ya'll are forgetting the most frequent variant (as pertains to Frontlines specifically):

Team A plays well (or more likely gets lucky) and takes an early lead.
Team B and C then spend the entire rest of the game tunneling Team A, both disregarding the map's objectives and failing to notice at any point both of them have long since overtaken Team A's score.
Team B and C continue doing this until the end of the match, thereby needlessly dragging it out through their own lack of situational awareness.
Team A meanwhile has been locked in a cycle of gaining and losing people since the moment B and C put them on the back foot.

Yup pretty much this seems to be most matches for me lol.

[Absurdity]

Ya'll are forgetting the most frequent variant (as pertains to Frontlines specifically):

Team A plays well (or more likely gets lucky) and takes an early lead.
Team B and C then spend the entire rest of the game tunneling Team A, both disregarding the map's objectives and failing to notice at any point both of them have long since overtaken Team A's score.
Team B and C continue doing this until the end of the match, thereby needlessly dragging it out through their own lack of situational awareness.
Team A meanwhile has been locked in a cycle of gaining and losing people since the moment B and C put them on the back foot.

Or Team C notices so while A and B keep duking it out and tunneling hard they silently overtake both.

[Zanarkand-Ronso]

Ya'll are forgetting the most frequent variant (as pertains to Frontlines specifically):

Team A plays well (or more likely gets lucky) and takes an early lead.
Team B and C then spend the entire rest of the game tunneling Team A, both disregarding the map's objectives and failing to notice at any point both of them have long since overtaken Team A's score.
Team B and C continue doing this until the end of the match, thereby needlessly dragging it out through their own lack of situational awareness.
Team A meanwhile has been locked in a cycle of gaining and losing people since the moment B and C put them on the back foot.

Or sometimes.
Team A gets an early Lead. The team is actually made up of Competent people who are either in a discord, or are just good at communicating in chat and working as a Group
Team B & Team C attempt to Dethrone them, but fail.
Now Team B and Team C shift focus on eachother, giving up all desires to win, and now the focus is to just not be Last.
Instead of fighting together against Team A to knock them out of 1st, now the Battle is for 2nd Place. Team A Wins

Thats been half my Experience at least, especially on Seal Rock.
Otherwise your description is perfect for Shatter