If you do not get any promotion, perks or increase of benefits during that time, your not going to get any ever.
Waiting with the mindset of "maybe I will this year" will only cause you mental anguish, to the point you'll become disgruntled and end up shooting yourself in the foot.
Why two years six months? It's takes three months of constant effort just to score an interview/new job and three to properly resign on pleasant terms or negotiate an upgrade.
Two years, is an substantial amount sum of time to work for a company and the bare minimum you should work in any company in my honest opinion.
Jumping ship will always bring more money. The truth is that businesses don't care much about you as much as they like you to believe. In that your forgotten in seconds flat and were only hired for your talent.
So why give it to them if they're not going to return the favour?