None of what you say makes any amount of sense. You can completely ignore the platinum chip. Only House and Yes Man care about the chip.
Needing Yes Man to take care of House makes even less sense. Because you have to kill House before you can do much of anything for Yes Man.
You're just running the Yes Man questline and wondering why you chose it. You could have gone NCR instead. Or done free roaming if you don't care about any of the four.
Does the game even end until you decide what to do with the platinum chip? I talked to House and didn't agree to do anything, there was just an optional quest in my journal. But I was still able to do accept the Yes Man quests. Needing Yes Man to deal with House makes plenty of sense given that I don't know exactly what House is, or how to defeat him, but here's a Securitron who has an inkling about the chip and how to use it.
Also, I ran the NCR quests up to Moore's quest to destroy House. Which I did. But at that point I was already required to return the chip to Yes Man. Now if you tell me I didn't have to give him the chip, that there was something else I could've done with it, then I'll smack myself and replay.
It doesn't force anything you PICKED YOUR ENDING by declining to meet with those people. Your ending being screwed up is 100% your own doing, you declined to meet with the ambassador or Caesar their messenger greets you outside of The Tops and the Lucky 38 respectively after first meeting with House and dealing with Benny at the Tops respectively.
No. I did NOT decline to meet anyone. I chose to pursue the Benny quest first because that quest drove the entire plot from the opening cinematic, but that closes off the NCR quests. I know I screwed up my ending based on my in-game decisions -- obviously. My contention is the story line assumes you're helping Yes Man once you've accepted his quest to grab the chip. But I could just as easily have turned the chip over to the NCR, or destroyed it, or just not pick it up. Did you even read my post before lecturing me?