that's are really good question! Let put it in an analogy in design do you reinvent all shapes of your design?
If you can build those things and you know how they work you can call yourself something.
I love the reasoning of reinventing the wheel ;D .... but lets go down to what happened ... you paid someone to build you a homepage and they used a template. That is common business usually a qualified person would not necessarily use an existing complete template but reusing existing parts is common.
It's hard to asses the work and the output based on 'they reused things that existed' this is like blaming you for your photoshop presets .... the amount of work needs to be tracked ... but if you went for a fixed price instead of hours that can be proven you somehow have yourselves to blame as well.
just the basic calculation -> i googled a standard fee for freelancer $70 per hour in north america that would mean you paid less than worth of 40h of work. The question of quality is something else. But for quality $2.5k ? the process alone of sitting with you guys talking on what you need and want and how it should be done, sending you different templates really would probably already cost half of it.
I understand you feel ripped of ... I don't say he didn't rip you off ... all I can say is that 2.5k is not much and if bad comes to worse it's cheaper to install a cache plugin + putting a reverse proxy (something like cloudflare) in front of your homepage to speed things up. So you can compensate for the slow hosting etc.
but without technical data or anything similar it's hard for me give any assessment besides things I can google and speak from experience.
But maybe some americans can provide better feedback Jason Knight for example.