Although they've always had a vocal fanbase, and reviewed completely, the Skate video games comprise never been seriously successful for EA, which is presumably why they've abandoned the rights to the trademark. EA still has a trademark on the IP, so it doesn't look like the publisher is prepared to drop the Skate series just yet.
Electronic Arts has had a pretty disastrous generation.
Electronic Arts seems to have ditched the Skate series because it chose not to renew the Skate trademark this year (via VG247).More news: Supreme Court to pronounce verdict on Ayodhya dispute tomorrow
EA aren't the sort of company you'd expect to be employing lackadaisical lawyers though, so the most obvious assumption is they abandoned the trademark on goal.
If you look over the trademark page on legal resource site Justia (thanks, GamesRadar), you can see the application history and the various attempts made to contact EA over the filing.
As noted by VG247, EA actually confirmed in its Q3 2017 financial call to investors that Skate 4 was not in development.More news: Megyn Kelly teases interview with ABC News Epstein whistleblower
Maybe it was the continuous demands for Skate 4 in the midst of other projects that caused EA to finally drop the franchise altogether in favor of their active efforts like Apex Legends and Star Wars. It is entirely possible that EA could re-file for the trademark like it has done previously. Skater XL exists with its own share of solid gameplay and is available now, and sometime in 2020, we're supposed to be getting the quirky, but also cool-looking Skate Birb.
That said, our hopes and dreams for now. It seems a Skate 4 is more unlikely now than ever.More news: Torrential rain in England strands shoppers, floods streets