The north London side finished in sixth place in the Premier League table in their final campaign under the French head coach Arsene Wenger.
The Gunners ended up 30 points adrift of Manchester City to highlight the size of the task facing Emery after his appointment.
Arsenal haven’t won the Premier League title since 2003-04 when the Gunners finished the season unbeaten under Wenger.
Emery has a lot of experience under his belt despite being just 46 following spells in charge of Almeria, Valencia, Spartak Moscow, Sevilla and Paris Saint-Germain.
The Spanish head coach led PSG to the Ligue 1 title this season after the capital club finished ahead of AS Monaco and Lyon.
But former Arsenal midfielder Parlour doesn’t believe the Gunners will win the Premier League title unless the north London side invest heavily in new playing staff.
“Unless there’s massive investment, the same as at Man City, [they’ll never win the league],” Parlour told talkSPORT.
“Man City will go out and buy the big players. If Pep Guardiola stays around and they keep trying to make the squad better, it’s going to be very difficult.”
Arsenal signed Borussia Dortmund striker Pierre-Emerick Aubameyang in a club record £56m deal in the January transfer window.
The Gunners snapped up Armenia international Henrikh Mkhitaryan in a swap deal from Manchester United.
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