It’s very well known that many counties (like professional rugby clubs) have been suffering, hence why the (very silly IMV) idea of ‘The Hundred’ was born - or could be still-born if some counties refuse the revenue/profit sharing terms.
T20 cricket for many counties has been a great boon but there are only so many ways to milk that cow, as interest in the County Championship has declined relative to the one-day competitions. The Test status of many grounds was put up for review many years ago and some (e.g. Old Trafford) were told they had to invest in the ground to get/maintain Test status (all very chicken and egg, with no promise of anything at the end), not missing the fact that more grounds have sought and acquired Test status (e.g. Hampshire (Ageas) Bowl/Cardiff/Durham being the latest IIRC, which have been added to the Test roster, partly to widen local public interest outside London which continues to enjoy Tests at Lord’s and The Oval come what may, leaving only 3 other berths per 5-match series).
AFAIK, outside of the usual functions and pop concerts which many grounds host, the vast majority of the Welsh/English grounds are single purpose unlike many of the Aussie grounds which share AFL/concerts and other events, with drop-in wickets (as per the new ground in Perth).
Like @Camphuw I’d be interested to understand how many of the counties strive to balance their books and if they truly do (ex benefactors), and what element they receive from any central source(s). Looking around the fringes of the England team and The Lions, I am not seeing the next crop of young players with Test potential (Archer/Currans excluded).