Few points of advice:

Give a set amount of sessions ('for 3 next sessions' instead of 'for a while').

Give them a choice (pitch two systems and let them pick which one to try out first)

Turn it into regular thing (every 4-5 sessions we have a one-shot of something different)

If they seem interested in one of the games, suggest 3 session switch.

Focus on those who say yes - do not ignore the naysayers, but you'll persuade them easier if you have a posse of your own. Tell the interested guys about the games, discuss character ideas, etc. You can also check before if one of them agrees for more support.

If two of them start to make a character, you have usually won. Pick a game with interesting chargen mechanics first and start with 'hey, let's at least create a character' - that usually warms up at least one additional player. Because...well...yeah, players love new chars.

Lead them through chargen, have handouts and charsheets, help them to build a char without reading through the whole book... and most probably they'll get hooked.

After all, why not do a test drive of the new char? Have a short one shot ready that showcases the best of the system.