Was thinking with the new PS Plus, that the old normal PS Plus would get devalued quite a bit. I think Games with Gold has been practically invisible to most users since the launch of Gamepass, so it seems like a distinct possibility.
It is a shame, the best time for PS Plus was with the instant game collection of June 2012- to June 2013. Practically 10+ games at once. This was before online was locked behind PS Plus too.
Now I think the only use for PS Plus would be online, so I think a month by month basis would be best for most users, but then it becomes more expensive.