Using the filibuster the way it's used now and not actually trying to come to a compromise is definitely new. It's not something that changed about the rule itself, but about the way it's used. See the graph in this article: https://www.statista.com/chart/25929/number-of-senate-filibu...

IMO it all comes down to the insight that the opposition party has nothing to gain from cooperating. If something good gets passed, the majority party gets the credit. If nothing gets passed, the majority party gets the blame, regardless details how that outcome was achieved and what role the minority party played. So blocking everything is the best strategy. IMO, it's disgusting to have politicians put party over country, but here we are.

> common in their current form since 1970 (that's 53 years not 10-15)

A chart of filibuster usage over the past ~century speaks for itself: https://bit.ly/3mL6IOU

And that's not even fully up to date: the 2019-20 session ended with 298 cloture votes and the 2021-22 session with 289, per https://www.senate.gov/legislative/cloture/clotureCounts.htm .

> the first filibuster was 11 years after the Constitution was ratified

Sure, whatever - your citation is "wikipedia.org/wiki/Filibuster_in_the_United States_Senate" and mine is "wikipedia.org/wiki/Filibuster#Senate". The exact details don't matter: the relevant points are that it's not a mechanism created by the Constitution, was not common in the lifetime of the Constitution's drafters, and has massively different effects on the governance of the country now than it did in the 20th century, much less the 19th or 18th.