The 1.5C threshold was more or less impossible from the time they first proposed it.
The current focus of climate policy on "net zero by 2050" essentially guaranteed it. Everyone is thinking about the long term and letting progress be really slow in the short term, letting the perfect be the enemy of the good. Solutions that could reduce emissions very quickly, like using natural gas as a bridge fuel to quickly displace coal & oil pending more nuclear investment and further development of energy storage tech, are being rejected as they're not "net zero".
IMO, the better approach would be to have a very aggressive emissions reduction target in the short term followed by a slower transition to net zero. Say 75% reduction by 2035 on the way to net zero by 2080. That way we could maximize investment on solutions that are ready to go now but just need more scale-up (like EVs for commuters, nuclear power, the wind/solar/battery trio, heat pumps for buildings, etc.) while leaving harder problems (like complete elimination of natural gas power & decarbonizing steel production) for later.
In electricity, Ontario eliminated coal, replaced only a small part of it with natural gas, and expanded wind, and is now expanding nuclear. As a result Ontario went from a grid that around 30-40% fossil fuel, mostly coal, to a grid that is now 94% carbon-free with the remaining 6% being natural gas only. It was a huge reduction in the carbon intensity of the power grid (IIRC, something like 85% less emissions per watt from 2005 to 2020). The small amount of natural gas used is critical to ensuring the reliability & stability of the grid. The net zero fetishists are extremely upset that Ontario has no immediate plans to eliminate that last 15% of emissions per watt by 2030; ignoring that there's way the province can do that without severe impacts on reliability and affordability of power (and it's not just an "anti-windmill government" saying that, it's
the civil servants in charge of the grid). In reality, Ontario did it right - focus on quick & early phaseout of what's feasible and leave the hardest, highest-hanging fruit for later.
By contrast, places like Germany whose entire plan is based on having an all-renewable grid in 30 years have actually
increased fossil fuel emissions in the short term. If the entire global economy had approached the problem the way Ontario did with its electricity grid, we'd have a higher chance of meeting aggressive temperature targets because there'd be a much larger reduction in emissions in the short term.