Most bikes now will be:Since there's some bike experts here, I thought I'd ask: I got a Norco Scrambler I bought for $500 in 2008. Specifically this: 2008 Norco SCRAMBLER – Specs, Comparisons, Reviews – 99 Spokes
What is it lacking compared to mountain bikes in the same class (entry level hard tail) being built today? Any reason to sell it and buy something modern assuming I'm just a casual biker?
1x10 instead of 3x7. Lots of gear overlap on 21 speed so you don't lose as much range as you expect
27.5 or 29" wheels instead of 26
Maybe lighter (but probably not at the $500 price point)
Aluminum has a finite fatigue life and if yours has been ridden a lot, it may develop cracks
Suntour fork isn't the best (but as above at $500, I wouldnt expect better).
If you are happy with it, I wouldnt bother switching.