There's also a certain amount of inertia at work. In many cars, simply replacing incandescent turn signal lamps with LEDs, for example, will cause them to flash erratically or not at all because of the way the flasher works. So now the flasher has to be redesigned or resistance added to the circuit. It's not a big deal, but it's still a change and an expense; so manufacturers monetize that expense by making it an add-on option.
We've had the ability to make a transistor flasher from a single IC since the 555 days, it's not really much of a cost.
Along those lines I did find that a number of places now sell replacement solid state flashers that directly replace the old click clack mechanical heating ones for nearly nothing. I'll have to put them on the Dodge and the Yukon for trailers that have goofy dual running/brake-flasher bulb setups.
My foray into automotive LED started with all the usual crap work done by GM on their dash clusters. Bad servos, bad grain of wheat bulbs, bad power supply driving the vacuum florescent display. If there was a screw up, GM made sure to make it.
Replace the servos, and more lights started failing. VFD started to dim. All signs it'd all fail. Found some dude online who rebuilds the things in his garage. Had him do the whole shebang. Replaced the grain of wheats with green LEDs to match the intended color of the cluster anyway. Those started failing a few months later (I suspect he used the wrong resistors with them or got a bad batch) months later finally got around to contacting him about his lifetime warranty. He agreed it shouldn't be doing that and fixed it. Free. Looks way better than original.
Then did all the marker lights on the fifth wheel for nearly nothing. Used T10 sized LEDs with outward facing panel of LEDs. Look great. Tried to do trailer tail lights. Figured out ground wiring is done wrong on trailer and need one of those solid state flashers due to current leakage from turn signal to running lights. Set those aside until I can get back to that project.
Realized the spare T10s fit the map lights in the Dodge and the rear overhead light perfectly. Stuffed three in there.
Same deal with the map lights on the Yukon. Look great. Side bonus, the original circuit slightly dimmed the map lights when they're selected on individually but not if the "all on" switch in the dash is used. Great that the effect is even higher with these particular LEDs. Never blinded by someone turning on a map light but ultra bright when doors are open or switch is selected. Awesome.
Did the back up lights on the Yukon. Awesome. Super bright. Way better than the originals. One is a little loose so I need to mess with it but a whack with my palm against the outer housing fixes it for a while. I'll get in there and squeeze the old connector together for a better fit one of these days when I remember.
Then did the DRLs. They're useless anyway but at least now they don't burn out constantly. GM screwed that up too which is why they went to the 4114. Less heat so they'd supposedly last longer in those little holders. Nope. Dead one every other year. No more of that.
Still working slowly on the project. Next will be the overhead lights in the Yukon and the mirror puddle lights. The floor lighting interior lights and the lights in the door kickjams.
Then I'll get the solid state flashers and spend a day figuring out and making sure the turns and brake lights all behave both with and without trailers connected and finish up the fifth wheel.
All in on the above I'm maybe $45? The trick is to find the non-name-brand stuff from China with decent reviews and buy from Amazon with their 100% return policy. One batch of T10s was all wrong for what I was doing so back in the shipping box it went. No biggie.
I won't do headlights. Anything that's putting off the proper light for driving rural at night has massive heatsinks and doesn't match the profile of a bulb at all. Sticks out the back or needs the light housing modified. Until I see someone say they did it on my makes of vehicles with cheap LEDs and has photos of it not making a mess, anyway.
Every interior bulb in the fifth wheel was also done in the first couple of months. That was about $20. That one helps a lot because if you're running off of house battery, much much less current draw. Better light too.
House: I always said it wasn't necessary but finally prices dropped on generic branded bulbs enough that $40 redid every bulb save two in the house. A few have their switching power supplies poorly designed in that they physically vibrate the bulbs and make them hum. Have enough spares it didn't matter. Just swap out the three noisy ones. Also got them in the traditional off-white similar color to incandescents, and you'd never know they're LED.
Oh. Forgot the very first ones. Outdoor lights. Out here I don't want to add to massive light "pollution" and found the perfect solution. 15W equivalent light LED appliance bulbs in all the outdoor sconces. Look great. Dim enough they're not lighting up the county, but enough to see keys for opening doors or whatever. Excellent. Those ran about $10 for the outside of the house. Those were the first ones I did. They're three years old now and on 24/7. No sign of dimming or wearing out.
