Believe who you want. I certainly don't trust politically paid "professionals" as much as you do. Its all how you decide to interpret data and what "professional" reports & criteria you feel is important in the overall scheme.
End of the day the Province has always built infrastructure based on Political drivers with "professionals" as support to their narrative. Scarborough has been on the short end of the stick all to often. And you can clearly see once again the Politically motivated propaganda machine like the Toronto Star with a non-stop attack on the SSE trying to ensure that continues. Tough to fight a political media powerhouse who is trying to put the funding for their own gain.
You make some valid points re: Scarboro and subways. In my opinion I wouldn't exactly say Scarboro 'got the short end of the stick', but rather that other boroughs / cities got a longer end. Subways in Vaughan? That's gotta be the stupidest, most political, and most insulting transit decision in our history. It's way worse than Sheppard, or Eglinton West. If an attempt was made to make it an affordable extension (i.e surface, elevated, simple stations, standalone light metro line), I could maybe agree - provided that other priorities were dealt with first. But no. Fully-underground 6 or 7-car heavy rail, fanciful stations, commuter parking lots, rammed through quick, admission of porkbarreling...it's a non-priority luxury and IMO VMC will never be as dense or urban as, say, STC.
Anyway, having said that, I put together a couple of charts that paint the 'short end of the stick' Scarb situation. Basically it shows existing/planned subway coverage within former boroughs/York Region. It must be noted however that while the second chart includes the Scarb Subway, the first chart doesn't include the SRT. As much as people despise the SRT, it is in fact a subway/metro line. Why I didn't include it is because it's not connected to our standard subway system, and bc it's slated for closure. But IMO it still should be included as a "subway", and I feel I'm lying by saying it's not.
So excluding the SRT - and prior to the SSE debate - Scarb had the lowest existing/planned level of subways per capita - even lower than a combined Vaughan + Markham. Per area it was still behind Etobicoke (but ahead of Vaughan + Markham). However including SSE, Scarb will have the third most subway coverage per area and pop - behind North York, but way ahead of Etobicoke. This was put together slapdash, so if anyone sees any errors don't hesitate to point them out.