Does not reflect my experience at all. T420 from 2011 is still completely usable. Haven't clocked the boot-up time but definitely not minutes, more like a couple dozen seconds. Everything worked out of box with latest stable Debian. Can do 2560x1600 over the DP connector, too. This is not even a top-spec model but the slowest i5 available back then.
How is battery life?
Also note that there are 16+ exchanges in the US with protected quotes. And 30+ dark pools (ATSs). There are many venues to trade.