No, they weren't hardcore gamers. Mainly business users.They definitely weren't gamers, then. I don't remember exactly, but I know $100 wasn't a lot for a 3D accelerated graphics card, back then. Sure, you could get some S3 or Trident cards for less, but you wouldn't if you cared at all about 3D performance.
If you're trying to stick to a rigid timeline, the Pentium 4 only launched at the end of 2000.
No, maybe you could still buy ISA graphics cards, but they would've been old models. Maybe you're thinking of VLB? Even then, from what I'm reading ATI didn't release one after 1994. Starting in 1995, they were all-in on PCI. AGP came after that, with there being some considerable overlap.
IIRC, AGP already had a 2x version, by the time it launched. Then came 4x and 8x.
No... definitely not "routinely". You basically have to get a RTX 4090 or else put a RTX 4080 or RX 7900 XTX in a budget build for that to be true. None of those cards are "routine".
I was making a timeframe relative reference. P3 or P4 was all priced in that range for flagship.
Yes, you could still buy ISA cards at that point (with the Vesa extensions). They were junk but still available for older systems and were certainly still sitting in my closet of spare parts and being used for repairs in the late 90s - early 2000s. The same could be said for PCI cards. AGP in that era was still bleeding edge and because of the quick version changes in AGP (and slot configurations for new versions) you pretty much had to buy a new motherboard for your new video card every time a new version came out so there were a lot of PCI variants available for retrofit because every computer at that time still had a PCI buss and a couple of ISA slots.
A PNY 4080 is running $1200 right now. I can go to Best Buy right now and purchase most of their desktops without a monitor for less than that. A 4070 at best buy is $600. I can still buy a fair number of their prebuilds for that. I would say that that qualifies as routine, at least from an overall volume point.