Someone just posted what I think are at least OK prices for 30" straights at around 11$ each. problem is you have to add shipping ... the cheapest I've seen retail is 299 ... if memory serves at "model train stuff"... anyway I've a box of that which I bought used for prices in that range and maybe half again as many I purchased kind of randomly until I realized I should stop doing that ... which means I've a mix of things which needs to be weeded in particular the O-36 curves and switches.
I will say that I found replacing the 10" with 30" where possible on my carpet layout, improved is reliability noticeably... but over time with enough runs, things will still loosen up.