For most of its 80-year history, Royal Crown Cola has had to come up with soft drink ideas first.

In the 1930s, that meant some simple but effective discounting: selling 12 ounces of RC for the price of a 6 1/2-ounce Coke.

Last month, it meant coming up with a new product--no-salt cola--while bigger firms laid back. But despite its record of innovation, the "other" cola company may not be around much longer in its present form, with or without salt, according to soft-drink industry analysts and observers.

Pressed by continued discounting and industry giants Coke and Pepsi, RC almost certainly will see its market share and profits decline, say analysts. A buy-out, a retreat from national merchandising or both are distinct possibilities.

"If inventiveness was the bottom line, RC would be the only company in the business. They'd make Coke and Pepsi look like private labels," said Jessey Meyers, editor of Beverage Digest, a widely read industry newsletter. "But marketing and finance are the key, and increasingly so, and it is becoming more and more difficult for RC to compete."

The firm's ancestor, Nehi Soft Drink Co., was founded in Columbus, Ga., in 1903, and for the first half of the century stuck close to its southern base. During the 1950s, as Pepsi caught up with Coke on the strength of its Pepsi Generation marketing push, Royal Crown Cola languished, a closely held company with neither the money nor, apparently, the inclination to expand.

Beginning with the 1962 introduction of Diet Rite, the industry's first sugar-free cola, Royal Crown came out with a series of product and marketing firsts.

"They were first with diet cola, first with the 16-ounce bottles, first with cans, first with caffeine-free" cola, said Tom White, president of the brand's Washington area bottler.

RC's most recent coup, caffeine-free RC 100, is a good example of what the firm can and can't do, as well as an indication of what may lie ahead for the no-salt product, according to E. F. Hutton analyst David Goldman. Introduced in mid-1980, RC 100 had the caffeine-free market to itself for nearly two years. In 1981, the product paced Atlanta-based Royal Crown Cos., Royal Crown's parent firm, to record profits of $37.3 million on sales of $450 million.

Troubles began with the introduction of Pepsi Free in July 1982. In less than a year, while RC 100's share of the supermarket soft-drink market grew from 0.9 percent to 1.3 percent, Pepsi Free picked up a 4 1/2 percent market share, Goldman said.

Profits for the second quarter of 1983, meanwhile, were off 7 percent from the same period in 1982, and RC was forced to discount to compete with Pepsi Free and Coke's later entry into the caffeine-free market.

"What Pepsi did was a matter of distribution and marketing muscle. RC is already playing catchup, and they were there first," Goldman said.

Further, Coke, with 1982 revenues of $6.2 billion, spends $5 for every $1 RC spends on promotion, advertising and marketing, "and that takes a toll," he said.

According to Montgomery Securities Inc. analyst Emmanuel Goldman, RC's size makes it a likely acquisition candidate for any larger firm attracted by its considerable cash flow.

Miami financier Victor Posner, a frequent player in major acquisitions, owns about 26 percent of the Royal Crown Co.'s stock, but has not commented on his intentions.

Whether or not the firm remains independent, some analysts think RC will be forced to adopt a regional, rather than national, marketing strategy, withdrawing from its weaker markets. Dr Pepper recently adopted such a strategy in an effort to make its promotional budget go farther.

"A reasonable strategy would be to concentrate your marketing and promotional bucks where they can do the most good. I'm sure the company is at least considering that," said Bonnie Cook, a beverage industry analyst for J. C. Bradford & Co.

Royal Crown spokesman Arnold Belasco said that RC "would like to remain independent" and had no plans to forsake its national marketing.