Pennsylvania: Used to have a Unicameral Legislature with a Collective Executive?

Factual Questions
1

I’ve been reading Isaacson’s biography of Benjamin Franklin, and one thing he mentions is that old Ben helped draft the new constitution of Pennsylvania in the revolutionary period, with a unicameral legislature and a collective executive, rather than a unitary governor.

Pennsylvania now has a unitary governor and a bicameral legislature.

So what happened to old Ben’s constitution? why the switch away from his constitution to the current one?

2

It didn’t last long. The 1790 constitution established a senate and house of representatives:

http://www.constitutionpartypa.com/pa_constitution.htm

3

And here is a list of state constitutions. Most states have redrafted their constitution a few times: