Big problem is that unlike most other counties, Middlesex don't own their own ground, so that most of the proceeds from (the very profitable) Lords go to the MCC.
There was a long article in the Sunday Times about this yesterday. Some extracts:
"External investment would be essential because Middlesex have recently been in dire financial straits, with irregularities under a previous regime culminating in the club being placed in 'special measures' by the ECB. To save money, Middlesex are not using overseas players this season.
In February, they posted a first annual surplus since 2016 of £131,000. However, their neighbours Surrey announced a profit of £8 million, in part due to their usage of the Kia Oval in south London, which they own, as a conferencing and hospitality venue."
"Reserves that once stood at almost £6 million have largely disappeared and a main sponsor recently pulled out. To save money, Middlesex are not importing any foreign talent this season."
"Middlesex have previously looked at developing sites at a former Barclays Bank ground in Ealing, [at Uxbridge Cricket Club] and at [Barnet] Copthall, but for various reasons the plans fell through."
"Along with Radlett Cricket Club, Merchant Taylors’ hosts a few Middlesex matches each season but neither is capable of being the kind of venue Middlesex would ideally possess; nor are they sufficiently central to draw 'London' crowds. In fact, in order to save on the cost of erecting temporary stands at either, Middlesex will this year controversially stage two 'home' matches at Chelmsford, the base of another neighbouring rival, Essex."
"A recent bright spot was the gift of a ground in Brentford from GlaxoSmithKline after the pharmaceuticals giant moved offices — the first ground Middlesex can call their own. It will be mainly used for the county’s women’s teams. 'It’s going to be a wonderful training facility and a wonderful opportunity to have summer camps,'" [said Angus Fraser]
(That last excerpt refers to the 4.5 acre playing fields at Swyncombe Avenue, which the ST says is in Brentford, despite it having a W5 postcode?)