That's kind of true and kind of not.
The bit of BT that provides raw networking wins regardless, and remains a near monopoly despite the gigantic (and usually calamitous) investments of various would-be competitors.
The problem is that that bit is regulated to the hilt, and so it's steadily profitable but not excitingly so. Because BT wins in a modest way regardless of who wins these bids their share price isn't affected and executives don't get their all-important bonuses.
The bit of BT that provides managed services on top only wins if BT win directly, and this is the bit that does impact all of the things above. Margins are made, bonuses secured and calves slaughtered in celebration.
The only corollary to this where PSN deals are concerned is that in my experience the winners often fare as badly as the losers. The framework contracts are bid based on a demand schedule so improbable that it would require every sheep to have their own ethernet circuit. Excited bidders then cut margins to the bone based on that theoretical demand that never materialises and large overheads are left uncovered at the end of the contract.
Margins are lost, bonuses withdrawn and calves have to be re-animated for sale at market to cover the mortgage.