You've still got another 1.5 years of security updates & probably two or three more point releases left, so not sure why you downvoted / disagreed with my earlier post about power pc to intel that was faster & harder.
Expensive is a relative term. To me expensive was;
- dropping £2.5k on a 17" MBP without AppleCare & having 3 logic board replacements within 3 years (granted I got refunded after the recall) but in the meantime was 'forced' to buy another MBP.
- buying an iPad 3 which lasted a whole 6 months before the 4 came out & the iOS support was cut short.
- persuading my then GF to buy the lampshade G4 iMac " £1800 which had support cut after 2 years.
By your own argument you're getting the 7 years albeit you're missing out one major release and all features probably wouldn't have been available to you anyway.
Transitions only happen thankfully every so often, this one will be fine for years to come.
Is it hard to stomach? Sure, but that's the way Apple rolls, I'm probably holding to the 3rd gen although that's my gamble given the iPad debacle, I'll probably cave in & get a M2 Pro next year.
Will your MBP stop working in 2 years? Nope it'll be fine (I've still got others that keep on truckin') otherwise suck it up, trade it in & get a M1/M2/M3 or keep it as a back-up.