Intel has already had so many flaws and vulnerabilities that I think nothing will change. People would prefer to ignore the problem and do nothing because they don't want their businesses to implode.
If lscpu still shows some offline cpus (let's say cpu 1 and 3 are offline), echo 1 >> /sys/devices/system/cpu/cpu<1 or 3>/online. Run lscpu again, and you should see all CPUs online and 2 threads per core.
Where are you seeing a performance burden? The spectre/meltdown patches had no impact to game performance: https://www.tomshardware.com/reviews/gaming-performance-melt...