From Wiki:
https://en.wikipedia.org/wiki/The_Dark_Side_of_the_Moon#Release
Sales
The Dark Side of the Moon became one of the best-selling albums of all time[103] and is in the top 25 of a list of best-selling albums in the United States.[56][104] Although it held the number one spot in the US for only a week, it remained in the Billboard 200 albums chart for 736 nonconsecutive weeks (from 17 March 1973 to 16 July 1988).[105][106] Of those first 736 charted weeks, the album had two notable consecutive runs in the Billboard 200 chart: 84 weeks (from 17 March 1973 to 19 October 1974) and 593 weeks (from 18 December 1976 to 23 April 1988).[107] It made its final appearance in the Billboard 200 albums chart during its initial run on the week ending 8 October 1988, in its 741st charted week.[108] It re-appeared on the Billboard charts with the introduction of the Top Pop Catalog Albums chart in the issue dated 25 May 1991, and was still a perennial feature ten years later.[109] It reached number one on the Pop Catalog chart when the 2003 hybrid CD/SACD edition was released and sold 800,000 copies in the US.[56] On the week of 5 May 2006 The Dark Side of the Moon achieved a combined total of 1,716 weeks on the Billboard 200 and Pop Catalog charts.[72]
After a change in chart methodology in 2009 which allowed catalogue titles to be included in the Billboard 200,[110] The Dark Side of the Moon returned to the chart at number 189 on 12 December of that year for its 742nd charting week.[111] It has continued to sporadically appear on the Billboard 200 since then, with the total at 988 weeks on the chart as of January 2024.[112] “On a slow week” between 8,000 and 9,000 copies are sold.[103] As of April 2013, the album had sold 9,502,000 copies in the US since 1991 when Nielsen SoundScan began tracking sales for Billboard.[113] One in every fourteen people in the US under the age of 50 is estimated to own, or to have owned, a copy.[56]
The Dark Side of the Moon was released before the introduction of platinum certification in 1976 by Recording Industry Association of America (RIAA), and therefore held only a gold certification until 16 February 1990, when it was certified 11 times platinum. On 4 June 1998, the RIAA certified the album 15× platinum,[56] denoting sales of fifteen million in the United States. This makes it Pink Floyd’s biggest-selling work there; The Wall is 23 times platinum, but as a double album this signifies sales of 11.5 million.[114] “Money” has sold well as a single, and as with “Time”, remains a radio favourite; in the US, for the year ending 20 April 2005, “Time” was played on 13,723 occasions, and “Money” on 13,731 occasions.[nb 7] In 2017, The Dark Side of the Moon was the seventh-bestselling album of all time in the UK and the highest-selling album never to reach number one.[115] As one of the blockbuster LPs of the album era (1960s–2000s), The Dark Side of the Moon also led to an increase in record sales overall into the late 1970s.[116] In 2013, industry sources suggested that worldwide sales of The Dark Side of the Moon totalled about 45 million.[3][117]
Nonetheless, if I am going back to 1973, it ain’t for Pink Floyd. Maybe How the West was Won with LZ.
Dark Side of the Moon was exceptionally well engineered / produced / recorded. Following “Abbey Road”, it really put Alan Parsons on the map. It was one of the best demo records for rock music to sell audio gear to sound quality conscious kids with a bit of money, that one could hope for.
You think your woofer can do bass? Hah! Crank up the opening to “Time” and see what comes or blows loose. Do that on the ol’ “ESS Rock Monitors” with the grill off and you’d likely blow stuffing out the port and into the sales room! Many a speaker would just crack and / or pop.
But, this was not a “bass heavy” record. The sound was beautifully balanced.