The iPad isn’t what it used to be.  

It’s been more than four and a half years since Steve Jobs launched the iPad.  On that first weekend of sales in May 2010, Apple sold over one million units against a backdrop of long, snaking lines at Apple stores – and tablet sales surged in the following years.  

Fast forward to the end of 2014.  For the first time since 2010, tablet shipments recorded a year-over-year decline in the fourth quarter, market research firm IDC said this week.  

The iPad just isn’t the sensation it once was, according to IDC. 

“Apple’s efforts to maintain iPad momentum have fallen flat so far,” IDC said in a statement, attributing this to the lackluster refreshes of the iPad Air and iPad Mini.   The new iPad Mini, for example, is virtually the same as the older model with the exception of a fingerprint sensor and a new color (gold).   

The problem is, when Apple slumps the whole market sinks.  The tablet market is “very top heavy” in that it relies mostly on Apple and Samsung to carry the market forward each year, IDC said.  

Which means Samsung is playing its part in the slump too. “Samsung's struggles continued as…mid- to high-priced Android tablets [like Samsung’s offerings] simply aren't cut out for today's tablet market,” the market research specialist added.  

What’s going on? Large-screen phones, aka phablets, are a big factor, according to market research firm Canalys, which also released numbers this week, showing a shrinking tablet market.  

Phablets, like the 5.5-inch iPhone 6 Plus and the 5.7-inch Samsung Galaxy Note 4, render tablets like the 7.9-inch iPad Mini less attractive and less necessary. 

“There are some markets around the world where five-and-a-half and six-inch smartphones are really popular [such as] China and other parts of Asia,” Chris Jones, an analyst and co-founder at Canalys, told FoxNews.com. 

“[In Asia] they are consuming media content on a large-screen phone so they don’t need a tablet,” he said.   “And Apple has [had an impact] as well, changing the size of their iPhone with the 6 Plus.  That has an impact because there’s not a lot of difference between a large phone and a seven-inch tablet.”

Jitesh Ubrani, an analyst at IDC, said that consumers are holding on to their tablets for a lot longer than expected, which is also contributing to the muted demand.  

One of the few bright spots is Microsoft and Windows device makers. They are tapping into a shift toward large-screen tablets in certain markets, according to both IDC and Canalys.

Microsoft has been aggressively pushing its 12-inch Surface Pro 3 tablet over the past six months and Hewlett-Packard markets 13-inch tablets to large corporations.  Both Microsoft and HP fared well in the fourth quarter, according to Canalys.

And Lenovo – a large Windows device maker – “had its best ever quarter,” said Canalys.

It should be noted, however, that the larger tablets are often marketed as hybrid tablet-laptops -- so growth in this market isn't necessarily good news for companies like Apple.  

And what can we expect in 2015?  

"Despite [the] slow-down of the market, we maintain our forecast about tablet growth in 2015," said Jean Philippe Bouchard, an IDC analyst.  

“Microsoft's new OS [Windows 10], a general shift towards larger screen[s]…and technology innovations such as gesture interface that could be introduced in tablets will help the market maintain positive growth in 2015,” he added.

Canalys expects growth in 2015 to come from tablets with screen sizes larger than 8 inches.