Sure, someone could sell a 300MHz scope with every feature and protocol decode under the sub for $500, and maybe even make some money from it.
But it won't be enough profit in order to do R&D for higher end products and stay in business.
That's not quite right. The low-end T&M market is a highly competitive and highly price-sensitive cut-throat market, and the profits are tiny unless you ship in big numbers. And even then it doesn't bring in enough dough to pay for any real R&D, and especially not for high-end products. If you're lucky it pays for product improvements or manufacturing/support cost reduction measures, but that's about it. This is the reason why Agilent has sold Rigol OEM stuff (apparently they now can make their own low-end stuff similarly cheap), and why LeCroy sells Siglent and Tek sells 10+ year old technology.
Manufacturers are not in this market because it rakes in huge profits, they are in because it increases brand awareness for their higher end products. And it's the higher end that offers huge profit margins (despite fewer sold products) and pays for most of the real cutting edge R&D costs.
Therefore no one is going to do it, it would be cutting the throats of the entire industry.
No, they won't do it because the current system of charging extra works extremely well. Why derail the gravy train?
The first company that does it will have a flurry of sales and them promptly go out of business, or just keep putting out mediocre products with no support etc.
If all this company makes is low-end stuff then yes, they perhaps would go bust because they selling the low-end scopes alone hardly makes them any money unless they can manufacture extremely cheap (as Chinese companies can do at the moment if they don't care for quality or working conditions) and sell a lot, and without a higher end that pays for R&D there would not be much money left.
It wouldn't be a a major problem for the big names, though, as they make most of their revenue from their higher end stuff anyways. Of course it would mean to voluntarily give up profits, which is a no-no in business, and therefore won't happen.
Big companies that put serious effort and money into developing new scopes and gear have to make enough profit back to stay in business to keep on doing that. So they do that by offering many price/performance options, and software options.
You seem to think that the price manufacturers charge for options somewhat reflects their own costs (i.e. development costs), but that is not the case. The price is set by what the manufacturer believes the market will pay, plain and simple. Of course there are some options that to develop have required noticeable investments, but these are generally found in high-end products and not in the low-end market (where the major R&D work for most options has already been paid by the high-end many years ago).
The only reasons why manufacturers get away with charging extra for even basic options on entry level scopes is because
- it's a very good way to squeeze additional money out of a market where profits are slim
- they can as their major competitors all do the same
- because they would look stupid if they charge enormous amounts of money for the software options for their high-end products when the cheap low-end variant comes with everything as standard (even when some of the high-end options were actually expensive to develop)
And I agree with kripton2035, these days basic stuff like I2C and RS232 decoding should really be free. But apparently the market bears that these options are charged extra, so it won't change any time soon.