encapsulating the roof for big $$$ vs yearly maintenance and inspection

i am wondering how many other co-ops owners are out there that are paying off assessments from roof encapsulating jobs.
What make this particular painful in our case is we have had the same managing company since the building went co-op over 25 years ago.
the roof is easily accessible by a stairway and a door , so it seems in over 25 years of paying this management company they never went up on the roof to inspect it and take care of the simple grouting and waterproofing every year.
instead they stick the shareholders with a huge assessment, that would have been easily avoided if they had simply done the job that they were paid to do .
IMO this is gross negligence on the part of the managing company .
anyone else getting hit with this ?