Well, technically Thor came closer than anyone to actually defeating Thanos in IW but this does raise an interesting question: why are all these people so obsessed with recreating the Super Soldier Serum when there are so many better super-power-granting chemical formulae around in the MCU?
Like the Extremis serum. Those guys were casually ripping apart Iron Man suits like they were cardboard. Or the Pym Particle, which is just ridiculously OP. Compared to those, the normal Super Soldier Serum looks a bit weak.
Like, if I was a wannabe supervillain in the MCU, I wouldn't bother with the SSS and instead would put my resources into getting ahold of one of those.