To be honest, that router costs 28 000 RSD ( https://www.gigatron.rs/ruteri/asus_dualband_wirelessac1900_... ) which translates in EUR to 236 EUR, so your point is not valid for outside of the USA. To get a feel for a router that costs exactly €50, see TP-Link MR3420 V5. Also, the router you mentioned (ASUS RT-AC68U has a dual core 800 MHz Broadcom processor and 256 MB RAM and 128 MB Flash storage, while most routers at 50€ have a 400 MHz Ralink/Mediatek Processor (single core) with 32MB (at most 64 MB) RAM and 4 or 8 MB SPI memory. ) I'm glad you happen to live in a country where you can obtain such a router for so little, I am not so lucky, so I use my ISP provided one that barely manages that 150 Mbps (thankfully with a Gigabit port (yes single LAN port)).
Yes, this is the discounted price because the hardware is a bit old. However, I think there are some decent affordable routers around the world. More so if you are open to ordering from China. I haven't been following the ultra cheap space too much, but you should definitely check out the forums. There are also APU2 boards (https://www.pcengines.ch/) that may provide a good bang for the buck. There's also old x86 hardware if you don't care about power consumption.
The only thing I've found that is acceptable to me is this: https://mikrotik.com/product/hap_ac2 (or "RBD52G-5HacD2HnD-TC", ... damn, don't they love the long-ass names). 128 MB RAM, Qualcomm processor quad core at 700 MHz (but ARM! :) ) and 5 gigabit RJ45 ports + Dual Band WiFi and a USB port! Plus, even if I can't get OpenWrt to work on it (though I prefer it), I can find my way with Mikrotik's RouterOS. I actually recently setup a PTP link at 3 km with 2 SXTsq's. Though I expected 100 Mbps, it only ended up being 72 Mbps stable, more than that and there's problems with the connection. I liked the old SXT more, you could put OpenWRT on it, the new ones use weird flash memory which OpenWrt can't write to...
edit: forgot to mention, it's 60€ brand new from a friend who works at a WISP
The firmware for routers like this is stored on SPI flash memory, and the size of the SPI flash chip determines how easily you can fit third-party firmware like OpenWRT on the router and how many compromises are necessary to do so. It's soldered on so not really user replaceable.
