Every decade has it's own points of concern including heat, electrical, plumbing, insulation and foundation.

Plumbing plumbing plumbing has been a major issue in this property, it’s one thing after another and by now I’m in it for like 3k just in plumbing related expenses and the plumbing issue is still not resolved!

Replace the plumbing, electrical, roof, and water heaters and you'll probably see the rates drop significantly. 

Another contractor upgraded our plumbing and then had an astronomical price to do the electrical upgrades that were not included in his estimate.

Typically there are laws about the property being maintained in a habitable condition with a limited time frame required to complete habitable related repairs, i.e. electrical, plumbing, heating, cooling, ...As a property manager, I agree with you that there seems to be "a lack of quality assurance" as well as a lack of communication and sense of responsibility from your PM. 

I am wondering how common lead pipes are (such as galvanized steel plumbing) for houses in Akron, especially houses built around 1945?

Alongside other NAR liaisons and committee leaders, Malta stressed the need for a more sustainable long-term solution to representatives from the National Economic Council and White House Office of Domestic Policy Council.After the executive order was issued on Sept. 1, Malta quickly urged consideration of housing providers who continue to fear wide-scale financial ruin in the prolonged absence of rental incomes.

Additionally, there are some major property components which aren't visible from a walk-through of the property, like plumbing and electrical, and assuming they need work is safer than assuming they don't.  

Purchase price: $195,000 Cash invested: $5,000 Historical house that underwent a complete gut job, new plumbing, electric, hvac, drywall, roof, insulation, after a fire that occurred at the property in 2019. acquisition also included a buildable lot in the back.

Items needing repair and/or replacement may include: roof, hot water heater, plumbing, heating and air conditioning unit, etc.