it's funny how the solution is always just 'let's go sign some players' like there is a never ending conveyor belt of quality footballers sitting idle for the Phoenix to call and ignoring all other influencing factors.
In general - yes, you are right. It is not always the only solution especially if the team plays like crap otherwise (Robbie Fowler at NQ Fury, anyone?)
In particular - right now - you are not correct. We could have turned the game around with a skilled energetic striker, on evidence of our performance against CCM (especially that one but also other games this season). In our last game we enjoyed healthy possession, yet did not seriously threaten a rookie CCM goalie more than a couple of times or so. After our leading goalscorer went off with a rolled ankle, our performance turned flat as a possum on a West Coast road.
Yes we should expect other players to take up the slack and we can blame them or the coaching staff if they don't. But we all know that Roly gets marked out of the game, and that McGlinchey is not an out and out striker. Powell took his opportunity this time, but he does not start every game. Sarpong was a non-starter. Appiah is a potentially decent squaddie but not a game winner.
We had a good season last year but we improved hugely with Burns on the park. Even that was not enough to take us far in the playoffs. This year, absence of a quality striker (in addition to Krishna) is clearly showing. This is in addition to the other influencing factors, as you said, and I acknowledge they also play part. Examples are: ill discipline or poor refereeing, injuries (Sarpong, Rufer, Lia, Sigmund), anxiety over licence.