you just covert via installing openwrt and bam you have a managed switch.
Your last line is relevant though, because 99% of users dont need 2.5gbit lan. I do get though that for specific niche uses such as maybe high speed NAS there is some demand for it, but if I do a quick google, I see people having similar thoughts to me, they look into it, see the price and are like "hell no".
They just need to get the prices down to no more than 1/4 of where they are now.
Sorry, do you know what a switch is? OpenWRT is a router operating system.
A managed switch is something entirely different and OpenWRT doesn't allow you to magically add features that the switch IC in the router doesn't support.
Most people don't know what Ethernet is, final.
Wireless marketing labels based on placing wireless devices 1mm apart inside a Faraday cage under lab conditions aren't even close to real world throughput though between rooms. Ethernet = You're usually guaranteed to get 90% of rated speed assuming a non-faulty half decent cable (eg, +900Mbps minimum for Gigabit on Cat6) as well as complete immunity to slowdowns / disconnects in Wi-Fi congested areas (apartment blocks, etc). Wi-Fi & Powerline technology = actual transfer rate is often barely 1/4 to 1/3rd of BS marketing figures. Typical
example review for an "866Mbps" device =
"Buffalo’s adapter performed much better than most of its competitors when the client was in my home theater (35 feet from the router), delivering TCP throughput of 227 megabits per second". Also Ethernet is Full Duplex, Wi-Fi only Half Duplex. 1Gbps Ethernet is also more energy efficient than many 2.5Gbps chips, something that's more important for the bulk of laptops that don't have Internet speeds anywhere near 2.5Gbps but always need more battery life. Gigabit Ethernet to 2.5 / 5 / 10Gbps was always going to be a slow & gradual transition.
You don't actually test wireless devices in a faraday cage, but rather in an anechoic chamber, or something like the chamber from octoScope with one of their multipath emulators.
Compact, stackable testbeds for automated validation and testing of Wi-Fi and 5G networks and devices.
octoscope.com
You're right that the marketing speeds aren't what you'll actually see in terms on throughput though, although as per the link I posted above, it seems like some equipment can now reach 1,500Mbps download speed over wireless, albeit my guess is that it would be inside the same room, but you should still be able to get Gigabit speeds a room away from the router. That said, there are no client devices that can reach these speeds, so it's a bit moot.
Gigabit only needs Cat 5e and if you don't get 950Mbps+ or more like 980Mbps today, you either have a devices that can't cope with the Gigabit speed, a busted cable or some really poor network drivers.
I doubt most people will notice that Wi-Fi is half duplex, since there are always some pauses in the transmission during which time data can be sent. That said, you're obviously correct that Ethernet is far superior to Wi-Fi if speed is the main target application.
2.5 and 5Gbps are actually quite new technologies and the transition to 2.5Gbps seems to be happening quite fast, mostly because Realtek and Intel made some affordable 2.5Gbps network controllers and PHYs, which meant the motherboard makers slapped them on their boards as an upsell/feature. We just need more affordable switches now, as 2.5Gbps doesn't need any better cabling than Cat 5e, which is a big bonus vs. 5 and 10Gbps.
Some pictures from back in the day when I was setting up the octoScope gear when I worked for a router maker. Note that the router pictured was just to make sure everything was working as expected before we started testing our gear.