How Much More Life For The Lincoln Cent ?

Some reduction is possible, but significant reduction that makes seigniorage from the cent possible again will not happen.
Unfortunately this is likely to be true. Coins as a money will probably disappear entirely before the cent stops circulating in the USA.

Congratulation to Canada! They figured out how to get rid of the circulating cent ten years ago! They also managed to get their one and two dollar coins circulating 35 and 26 years ago respectively. They are clearly the superior nation!

you still have intact gears?

Eliminate the cent, nickel and quarter. Reduce the size of the half dollar to roughly that of a nickel, create a $2 coin. Make the remaining coins plated steel (10c, 50c, $1, $2), each with a unique shape/edges (7-sided half, round plain end dime, reeded dollar, skip-reeded $2). Then eliminate the $1 and $2 bills. In 3-5 years create a $5 coin and eliminate the $5 bill.

As for coin designs, take the current designs and rotate them amongst the remaining coins. For 2025, the 10c has Lincoln, 50c has Jefferson, $1 has Roosevelt, $2 has Washington, then in 2026 the 10c has Kennedy, the 50c has Lincoln and so on). Alternately have half the dimes with Lincoln, half with Roosevelt, half the 50C with Kennedy, half with Washington, half the $1 with Sacagawea, half with Jefferson. The varying commemorative designs can be transferred to the $2 coin to increase awareness of it.

With purchasing power of the dollar roughly 10% of what it was in 1960, the dime can become the new "penny" without the stigma of a devaluation.

Of course this is all just a mental exercise as coins will become useless in a few years as card and electronic payments filter down to the smallest of purchases and even the unhomed and unbanked acquire electronic and card payment means. I fully expect the end of coins by the 2030's and the end of cash in all formats by the 2040's.

Rounding of taxes goes beyond the 1/2 Cent. Just look at various taxes that are based on Mills. Property owners aren't charged $1000.0001, the figure is rounded according to the established rules to the Cent. Sales taxes are commonly calculated to where there would be fractional Cents, but the cash register handles the math.
If the Cent is dropped, it would be rounded to the next smallest denomination, the Nickel. Rounding is bidirectional, so the argument that you're going to be charged more by "rounding up" is not grounded in fact, nor in light of the way rounding works today.

IMO, the Nickel should be dropped too, making the Dime the smallest denomination coin in the USA. Negative seigniorage on the Cent and Nickel costs millions. With 4,920,000,000 Cents minted in 2022, at a cost of 2.41¢ each, that's a loss of $69 Million Dollars. The US Nickel at 11.18¢ per coin, and 1,047,360,000 produced in 2022, that's a negative seigniorage of almost $65 Million on Nickels.

Who pays for the loss? We all do. Who benefits? Producers of copper, nickel, and zinc.
I honestly can't remember the last time I paid for anything with part of the price being in Cents. I'm certain it's been a couple decades. Unless I suspect they're 95% copper, I walk past them in the parking lot.
And, it has been estimated that every year, millions of Cents are intentionally, deliberated, literally, thrown in the trash. Cents that cost a couple Cents each to mint.

Well stated, Vector Ze, and to the Community!

Yes, jbuck, has the answer...!

Congress won't act first, but if enough businesses, big and small, enacted the "ROUND DOWN" policy on cash payments then eventually (10 years at least?) reduced demand for the penny could incite Congress to get rid of the penny. But the key, as @JBuck said, is to round down on cash payments. Charge to the cent on credit and electronic payments if you want, but round down on cash payments and nobody can argue against that!

PS: I am a HUGE fan of the penny, or one-cent coin as we call it, BUT even I agree it's time to go. If nothing else, the Zincoln is an environmental disaster (but I'll forego that discussion).