The courts would likely require the PMC to refund the tenant and then pursue you for reimbursement -> that would cost them time & money IF it made financial sense to hire an attorney to chase you.Kudos to @Adam Bartomeo for getting this right!

Case in point, home repair and reno costs are up since 2019.

How much is the average cost for the upgrade? 

That's my opinion.Another good one is AppFolio, but this is very costly.

The owner would cover the cost during vacancies and within the first week or so of a new tenancy if needed as a courtesy.

Bridge Loan: Most lenders on BiggerPockets will offer 85-90% of the purchase price plus 100% of the rehab costs.

Unless you are an attorney practicing real estate in the state of the subject property, the chances of reaching a wrong conclusion are too great and the consequences too costly.  

Is it because the cost of their service is fixed and therefore they try to do as little as possible, or is it something else?

The buyer agreed to a purchase price and all fees/costs.

Many clients from Canada also boast that pricier neighborhoods in the U.S. for example Miami, are only a fraction of the cost of properties in Canada, so their ROI is much higher.