To lower the cost of insurance so everyone can afford it right? And if the individual mandate is stricken can everyone still afford it?
You're mixing up a number of concepts here: cost control, affordability, and risk selection.
The "affordability" component of the law refers to the limitations on the percentage of a person or family's income that will go toward health insurance premiums (unless they wish to spend more). That's achieved in the exchanges for people under 400% FPL via the refundable tax credits. Outside the exchanges, it generally just means that if your premiums will cost more than a given percentage of your income, you're exempt from the mandate and can buy one of the catastrophic plans available to "young invincibles" (i.e. people under 30), regardless of your age.
Exchange premiums will be higher in the absence of the mandate (and enrollment lower), but that doesn't change the affordability standards. Your premium contribution is still pegged to your income.
The law has a number of cost controls but the ones that relate to the private insurance market reforms are: 1) the organizing of the individual market into exchanges, and 2) the structure of exchange subsidies, which are competitively bid by tying them to the 2nd cheapest silver plan.
Neither one of those is affected by removing the mandate.
As I've already pointed out, the individual mandate exists solely to manage risk. Right now that's generally done via underwriting, but underwriting is largely eliminated by that infamous 2 pages of the ACA. Without the mandate, exchange premiums will be higher because higher risks will be more likely to enroll than lower risks. The purpose of the mandate isn't to lower premiums, it's to avoid or mitigate that rise in premiums.
As I've said probably a half dozen times now, the individual mandate's reach doesn't extend beyond the guaranteed issue/community rating rules in 2 pages of the legislation. If you were to eliminate the mandate, there's no justification for eliminating anything in the legislation beyond those 2 pages.